text:
# Riemann Geometry and Physics

• I
Killtech
In terms of diff geo it seems like an obvious fact, that a manifold can be equipped with quite a variety of different Riemann metrics. But when it comes to physics (relativity theory in particular) it seems there is a very specific metric singled out. Now i do not entirely understand the connection between physics its mathematical formulation, but that is what i intend to find out.

So my understanding of Riemann geometry is that whether a surface has curvature or not depends entirely on the metric the manifold is equipped with. Furthermore there are many other metrics a manifold can have and the identify function should act as a pullback between them - since those are Riemann metrics i don't see how they could have incompatible topology amongst each other to to break the smoothness of ##id##.

So given a problem (e.g. an equation) on a specific Riemann manifold there should be no issue to pull it back to any other geometry (same manifold, different Riemann metric) and have an equivalent description of the problem there. My question is now if there is anything that distinguishes a specific and unique metric as in "the real depiction of the surface e.g. how it's really curved". Until now my understanding was that one metric is as good as another and if a distinction is made it's just for pragmatic reasons.

So far my naive view was that curvature was merely something resulting from how we chose to measure distances and therefore by itself not inherently a physical entity, which is dictated by nature. On the other hand i am very well aware that any information contained in the curvature of a physical problem is crucial, but i wonder if that's the only way to depict it.

Staff Emeritus
If I understand what you're asking, you're right, that a metric has no physical significance until you relate it to physically meaningful quantities.

The spatial component of the metric is used for computing lengths of objects. That has no physical significance unless you add the physical assumption that, in many situations, the length of a rigid object is unchanged as a function of time, and is unchanged by rotations and translations. Those properties of a rigid object are important for there to be such a thing as a "meterstick". If sticks were not rigid, but were instead stretchable like putty, then you couldn't use them to measure.

But given that there are such things as (approximately; no object is rigid in all possible circumstances) rigid objects, then the metric, and curvature (which is computed from the metric) is a physical property.

The metric also defines what is known as "geodesics", which is the analog of "straight lines" in curved space (actually, to define geodesics, you don't necessarily have to have a metric, but if you do have a metric, then geodesics can be defined in terms of the metric). Geodesics have very little physical relevance until you can connect them to the behavior of physical objects. The connection is through Newton's first law (which generalizes to curved space): An object in motion continues motion in a straight line unless acted upon by an external force. So you throw a rock, and assuming that electrical forces, friction forces, etc., are all negligible, then the path of the rock will be a geodesic.

(A difference between Newtonian physics and General Relativity is that for Newton, gravity was an external force, causing a rock's path to veer away from straight-line motion. For General Relativity, it is assumed that gravity is a manifestation of curved spacetime, so the path of a thrown rock is (approximately) geodesic even when there is gravity.)

Staff Emeritus
Homework Helper
Gold Member
2021 Award
Furthermore there are many other metrics a manifold can have and the identify function should act as a pullback between them
I'm not really sure what you are saying here? Are you saying that the identity function from the manifold to itself should let you pull one metric back to become another metric? If so that is not the case, the identity function on a manifold pulls a metric back to the same metric. You can relate some metrics to each other by considering the pullback of a metric tensor under an automorphism of the manifold, which will generally relate the metrics simply by a coordinate transformation. However, this is not necessarily the case for arbitrary metrics. For example, the pullback will preserve things like curvature scalars etc so you cannot pull back a zero curvature metric and get a metric corresponding to non-zero curvature. In this sense, you cannot change the geometry of the Riemannian manifold using the pullback of an automorphism.

A very important concept is also that of Killing fields, which generate symmetry transformations of the manifold, i.e., the pullback of the metric under the symmetry transformation is the metric itself.

So far my naive view was that curvature was merely something resulting from how we chose to measure distances and therefore by itself not inherently a physical entity, which is dictated by nature. On the other hand i am very well aware that any information contained in the curvature of a physical problem is crucial, but i wonder if that's the only way to depict it.

On the contrary, curvature and more generally the geometry of a Riemannian manifold is something tangible that cannot be changed just through an automorphism's pullback.

PeroK
Killtech
If I understand what you're asking, you're right, that a metric has no physical significance until you relate it to physically meaningful quantities.

The spatial component of the metric is used for computing lengths of objects. That has no physical significance unless you add the physical assumption that, in many situations, the length of a rigid object is unchanged as a function of time, and is unchanged by rotations and translations. Those properties of a rigid object are important for there to be such a thing as a "meterstick". If sticks were not rigid, but were instead stretchable like putty, then you couldn't use them to measure.

But given that there are such things as (approximately; no object is rigid in all possible circumstances) rigid objects, then the metric, and curvature (which is computed from the metric) is a physical property.
Yeah, this is an aspect i was thinking a lot about lately. In particular about the assumption that a rigid object, i.e. the "meterstick" length is unchanged. The structure of Riemann geometry makes me think this postulate is not physical in nature, given the circular definition of any real length measure. I mean how would you know that a meterstick doesn't change length? you have to measure it and every measurement requires comparing your sample vs a reference measure i.e. another meterstick.. so I'm not sure it's logically undecidable if it really does change and it would seem that at some point some meterstick must be simply defined as constant. Poincaré pointed out this problem in a letter from 1904.

But looking at the math i instead got the idea that it doesn't really matter because it's totally sufficient to think of all length measurements as in units of the local length of the meterstick rather then an invariant absolute value. A length measure defined via such a physical meterstick would then only require to suffice the properties of a metric, so even if we consider a stick not being rigid but having a well defined length at each point and direction of space time (Come to think of it this may be a very physical depiction of the metric tensor) it should suffice to define a Riemann metric - at least its purely spatial components (strictly speaking this is not true for the original meter bar in Paris, because it's length at a point of space time would depend on the way it got there. That's a bigger problem then it not being rigid). That at least would fit well with the picture that a manifold has many Riemann metrics to chose from and none is naturally highlighted as the real on in terms of mathematics.

Using different physical objects as reference for length that might change their relative length compared to each other would therefore merely represent different Riemann metrics physics could be represented with. As such there would be no absolute way to say whether a body is rigid in general, as this would depend on the choice of metric.

The metric also defines what is known as "geodesics", which is the analog of "straight lines" in curved space (actually, to define geodesics, you don't necessarily have to have a metric, but if you do have a metric, then geodesics can be defined in terms of the metric). Geodesics have very little physical relevance until you can connect them to the behavior of physical objects. The connection is through Newton's first law (which generalizes to curved space): An object in motion continues motion in a straight line unless acted upon by an external force. So you throw a rock, and assuming that electrical forces, friction forces, etc., are all negligible, then the path of the rock will be a geodesic.

(A difference between Newtonian physics and General Relativity is that for Newton, gravity was an external force, causing a rock's path to veer away from straight-line motion. For General Relativity, it is assumed that gravity is a manifestation of curved spacetime, so the path of a thrown rock is (approximately) geodesic even when there is gravity.)
About Newton and GRT. I wondered if a core difference between those theories could be interpreted that Newtown actually uses a different metric? I try to sketch how i get there: consider Newton and Einstein describing the identical scenario of a spherical mass (think of the Schwarzschild solution for a Earth proxy). Consider both building rings at different radiuses and measuring their length. in GRT space curvature will make it deviate from the ##2 \pi r## formula, so Newtowns case he will find his Euclidean geometry mismatches the measured data. Couldn't he therefore conclude that the 1-SI meter(stick) must change its length depending on its space location (in particular the gravity potential)? So he would have to presume his theory measures lengths differently then the measurement devices do but using a pullback to their metric could remedy it, no?

Last edited:
Killtech
I'm not really sure what you are saying here? Are you saying that the identity function from the manifold to itself should let you pull one metric back to become another metric? If so that is not the case, the identity function on a manifold pulls a metric back to the same metric. You can relate some metrics to each other by considering the pullback of a metric tensor under an automorphism of the manifold, which will generally relate the metrics simply by a coordinate transformation. However, this is not necessarily the case for arbitrary metrics. For example, the pullback will preserve things like curvature scalars etc so you cannot pull back a zero curvature metric and get a metric corresponding to non-zero curvature. In this sense, you cannot change the geometry of the Riemannian manifold using the pullback of an automorphism.
Hmm, okay. Well, there are different types of manifolds i guess and we are not talking about the same here. Consider the identity function as acting only on the bare set of ##M## and forget about it knowing about any other structures defined on it maybe.

Perhaps i better make a concrete example: consider a smooth 2 dimensional manifold ##M## and a coordinate chart ##\phi##. Now let's suppose that someone lost the information about what surface ##M## actually was and we don't have its metric anymore - i.e. we only know how it looks via its coordinates. So we have to look at the possibilities: it could have been just flat surface or maybe it was part of a sphere with a curvature? We can equip ##M## with the possible Riemann metrics for either of those cases, but the set ##M## itself stays identical and we could go from one option to the other by using the ##id## function on the set of ##M##. So ##id## actually maps between two different Riemann manifolds - which is a bit confusing i admit. Now ##id## will be bijective in any case but smoothness requires the topologies on both sides to agree. Anyhow i don't see how ##id## would remain isometric for that case.

Last edited:
Staff Emeritus
Yeah, this is an aspect i was thinking a lot about lately. In particular about the assumption that a rigid object, i.e. the "meterstick" length is unchanged. The structure of Riemann geometry makes me think this postulate is not physical in nature, given the circular definition of any real length measure. I mean how would you know that a meterstick doesn't change length?

Well, you would certainly know if different metersticks changed size in different ways. Then two metersticks that started out the same size would end up different sizes.

If you're asking whether it's possible that everything in the whole universe changed size in exactly the same ratio, so comparisons never changed, well, that wouldn't be observable. In that case, you could just define the length of something to be the length relative to a standard. Then by definition, if the ratio didn't change, then the lengths would be constant.

There is a certain flexibility or tradeoff between "laws of physics" and "geometry". If you wanted to define the surface of the Earth to be a flat plane, you could do so, but then you would find all sorts of effects, such as the lengths of objects changing as you move them around.

The only thing that you can physically test is the combination of particular laws of physics with particular assumptions about geometry. You can't test the two completely separately (I don't think). For example, in a rotating coordinate system, there is an apparent "centrifugal force" seeming to fling objects away from the center of rotation. Properly understood, this is not an actual force, but is a manifestation of geometry.

You could, however, attribute it to a physical force, instead of geometry. That is, you could assume that your coordinates are not rotating, but that there is some strange "anti-gravity" emanating from the center, pushing things out. That's certainly a possible interpretation, but it would lead to a strange theory, because there is no source to this force field. There's no actual object in the center that could be the source of some kind of anti-gravity.

So the choice between what's geometry and what's physical forces is not completely determined, but we choose the geometry that makes the laws of physics as simple as possible.

But looking at the math i instead got the idea that it doesn't really matter because it's totally sufficient to think of all length measurements as in units of the local length of the meterstick rather then an invariant absolute value.

Right. I guess I should have read this before responding with the above.

About Newton and GRT. I wondered if a core difference between those theories could be interpreted that Newtown actually uses a different metric? I try to sketch how i get there: consider Newton and Einstein describing the identical scenario of a spherical mass (think of the Schwarzschild solution for a Earth proxy). Consider both building rings at different radiuses and measuring their length. in GRT space curvature will make it deviate from the ##2 \pi r## formula, so Newtowns case he will find his Euclidean geometry mismatches the measured data. Couldn't he therefore conclude that the 1-SI meter(stick) must change its length depending on its space location (in particular the gravity potential)? So he would have to presume his theory measures lengths differently then the measurement devices do but using a pullback to their metric could remedy it, no?

Yes. There is no such thing (as far as I know) as an effect that absolute cannot be explained using Newton's physics, with flat space and absolute time, as long as you're creative enough about making up new, weird forces. Before Einstein, people did attempt to explain things such as the null result of the Michelson-Morley experiment by proposing forces that physically affected the lengths of rods and the timing of clocks as they move around. It can be made to work, but it's a lot more complicated than Einstein's approach, which makes use of a different spacetime geometry than Newton used.

Killtech
Killtech
If you're asking whether it's possible that everything in the whole universe changed size in exactly the same ratio, so comparisons never changed, well, that wouldn't be observable. In that case, you could just define the length of something to be the length relative to a standard. Then by definition, if the ratio didn't change, then the lengths would be constant.
i don't exactly understand your premise here. You can define various physical objects or length which do change relative to the SI-meter depending on where they are (and in a well defined way). My thinking was that one could equally set these things to have constant length instead thus rendering the SI-meter to not being constant.

So the choice between what's geometry and what's physical forces is not completely determined, but we choose the geometry that makes the laws of physics as simple as possible.
Yeah, that is exactly my thinking. But what the simples possible form laws of physics can take is always depending on the context of your problem, no? For me it looks like in this regard the metric/geometry resembles coordinate transformations in that you could switch between them to simplify your problem. But coordinates are chosen purely for practicality and there is no point of thinking of any choice as the actually "true" or "real" one.

Case in point, when dealing with acoustics, one could you just define a measure of length by using sonar location for distance measurement? due to the properties of the medium the speed of sound differs locally but is well defined to suffice as a metric in regular circumstance i think (ofc, not in a vacuum), so if you measure 1 SI-meter in different locations in terms of the two-way speed of sound the results will deviate. But using the special metric should simplify acoustic physics by rendering the speed of sound artificially constant - at the expense of adding curvature to a previously flat space.

Yes. There is no such thing (as far as I know) as an effect that absolute cannot be explained using Newton's physics, with flat space and absolute time, as long as you're creative enough about making up new, weird forces. Before Einstein, people did attempt to explain things such as the null result of the Michelson-Morley experiment by proposing forces that physically affected the lengths of rods and the timing of clocks as they move around. It can be made to work, but it's a lot more complicated than Einstein's approach, which makes use of a different spacetime geometry than Newton used.
Hmm, you arrive at the very same conclusions i have. I take it as a good sign that I'm not going nuts :). However don't think getting creative in finding ways to fix Newtons physics would be very productive. I would rather look for a way to identify the metrics of Newton and Einstrein and try to find a pullback between them in order to have a clearly defined way to translate all laws of physics from one geometry to another. I mean i would assume there could be some simplifying advantages of having a flat space time. And going back to the example of the 1-SI meter changing length in Newtown's grav potential - by the definition of the meter via the speed of light it implies it's not constant there as well. So Maxwells equations in vacuum would have to get something like a refractive index induced by Newtowns gravity - i.e. something resembling a medium. if a pullback to that geometry existed a Newtonian equivalent of Maxwell could be calculated from GRT right away, right? It would be interesting to know if the old aether theories (like the one originally used to explain Michelson-Morley result) could actually be equivalent to GRT but using a different metric.

Anyhow i don't want to discuss the details of such a approach here but rather trying find out if my way of thinking about this has any major logical flaws or oversights. So i welcome pointing out wherever the math does not warrant such interpretation.

Staff Emeritus
Yeah, that is exactly my thinking. But what the simples possible form laws of physics can take is always depending on the context of your problem, no?

No, I don’t think so. It’s true that geometric effects can look like physical forces. For example, the apparent centrifugal force. But that doesn’t mean that choosing what is forces and what id geometry is arbitrary. Geometric effects have certain universal qualities: They affect all objects in the same way, and they have a characteristic dependence on the velocity of the object. And, more to the point, the effect on test particles can always be locally eliminated by a coordinate change.

That’s not true for other physical effects. If you have an electric field, for example, it affects positively charged particles differently than negatively charged particles. This difference cannot be transformed away through a coordinate change.

Killtech
No, I don’t think so. It’s true that geometric effects can look like physical forces. For example, the apparent centrifugal force. But that doesn’t mean that choosing what is forces and what id geometry is arbitrary. Geometric effects have certain universal qualities: They affect all objects in the same way, and they have a characteristic dependence on the velocity of the object. And, more to the point, the effect on test particles can always be locally eliminated by a coordinate change.

That’s not true for other physical effects. If you have an electric field, for example, it affects positively charged particles differently than negatively charged particles. This difference cannot be transformed away through a coordinate change.
It is clear that all the information contained within the geometry cannot simply get lost via a transformation, so it has to transform into something else. My thinking was not about trying to choose what should be a force and what geometry - but merely chose a different metric and see what happens: If a map can be constructed between the original manifold and the new one arising by equipping the same space with the new metric (the map should therefore be based on ##id## of the underlying space) and that map is homeomorph - then pulling back laws of physical via that map cannot lose any physical information - therefore giving an equivalent description of the very same physics in the new metric. Therefore whatever metric you choose, gravity cannot ever vanish but rather must take some different form.

And about geometries affecting all objects in the same way - it is certainly true, yet the meaning of "same way" is perhaps misleading.

I'll try to make a simple purely mathematical model to sketch that thought. Consider the Minkowski space with only two fields for which the Maxwell equations ##m_1## holds (assuming charge and current always to ##0## for this example). Now let's pick some specific cartesian coordinates and add another two fields for which another Maxwell equations ##m_2## holds that however differs only by using having a different ##c_2## in that particular coordinates. Let's do a Lorentz boost: ##m_1## will obviously be invariant, but because ##m_2## adheres to a different Lorentz group associated with ##c_2## its transformation becomes quite messy. This can be remedied however by it pulling back to its natural Minkowski space arising from ##c_2##. Within that geometry ##m_2## becomes Lorentz invariant but this comes at the expense that ##m_1## won't be anymore. Now i don't think a geometry exists that can achieve both equations to have invariant transformation behavior at the same time, so in terms of Riemann geometry we can construct a case where we have two distinct native metrics for the same space where all physics (##m_1## and ##m_2##) take the simplest possible form.

Last edited:
Killtech
I'm not really sure what you are saying here? Are you saying that the identity function from the manifold to itself should let you pull one metric back to become another metric? If so that is not the case, the identity function on a manifold pulls a metric back to the same metric.
The simples case of what i have in mind would be a Weyl transformation. This also uses the ##id## for the pullback. But in this scenario ##id## is neither an automorphism (no self mapping) nor an isometry - as it maps between two actually different metric spaces. It should only be self-homeomorphism in the topological sense because it is a mapping to the very same topological space.

However i don't want the restriction that limits the transformation to remain within the same conformal class.

Last edited:
Staff Emeritus
Homework Helper
Gold Member
2021 Award
It is not clear to me what you are trying to do. An induced metric is the pullback of the metric in the target space of the embedding to the embedded space. The embedded space does not a priori have a metric - the induced metric becomes what it becomes. If you take a manifold M and it can be made a Riemannian manifold (M,g) by the introduction of a metric g, the pullback of g using the identity mapping (i.e., embedding M in itself using the identity map) is going to be g itself - not a Weyl transform of g.

Killtech
It is not clear to me what you are trying to do. An induced metric is the pullback of the metric in the target space of the embedding to the embedded space. The embedded space does not a priori have a metric - the induced metric becomes what it becomes. If you take a manifold M and it can be made a Riemannian manifold (M,g) by the introduction of a metric g, the pullback of g using the identity mapping (i.e., embedding M in itself using the identity map) is going to be g itself - not a Weyl transform of g.
Oh, no no no. I'm definitively not talking about an induced metric. Okay maybe i call my map ##\phi## instead of ##id## to point out it maps between different metric spaces. Furthermore i don't want to pullback the original metric, therefore the image of the map is not an embedded space.

Think of the two different Riemann manifolds ##(M,g)## and ##(N,h)##, except that ##M## and ##N## is actually the same topological space... so ##\phi: (M,\tau) \rightarrow (N,\tau) = (M,\tau)## (where ##\tau## ist supposed to be the topology). Only in that sense ##\phi## is the identity function. You could still pullback ##g## to ##N## but if you do that the induced metric will be exactly ##g## again - as you said yourself. However i explicitly wish to change the metric by not using an isometric map. So in this case if ##g## and ##h## disagree ##\phi## is no isometry, right?

And technically if ##g = f h## for some function ##f>0##, then ##\phi: (M,g) \rightarrow (M,h)## would be a conformal map i.e. a Weyl trafo. but again, i don't really want to restrict to that special case.

Last edited:
Staff Emeritus
Homework Helper
Gold Member
2021 Award
But that is not a pullback then as you wanted in your OP. It is just a map between different geometries. Different geometries will have different physical characteristics - curves will geerally be of different lengths, angles will be different etc. The geometry is part of the physical description and so the physics are different.

Staff Emeritus
But that is not a pullback then as you wanted in your OP. It is just a map between different geometries. Different geometries will have different physical characteristics - curves will geerally be of different lengths, angles will be different etc. The geometry is part of the physical description and so the physics are different.

I think that @Killtech is saying that the same physics can be described by different geometries, if you also adjust the forces (and the laws for how matter and energy affect geometry).

It's sort of trivially true. Suppose we pick some coordinate system ##x^\mu##, and according to the "true" laws of physics (say, General Relativity plus some force law), the path of a particular particle is given by:

##\dfrac{d U^\mu}{d\tau} = F^\mu - \Gamma^\mu_{\nu \lambda} U^\nu U^\lambda##

where
• ##U^\mu = \dfrac{dx^\mu}{d\tau}##
• ##d\tau = \sqrt{g_{\mu \nu} dx^\mu dx^\nu}##
• ##g_{\mu \nu} = ## the metric tensor
• ##\Gamma^\mu_{\nu \lambda} = \dfrac{1}{2} g^{\mu \sigma} (\partial_\nu g_{\sigma \lambda} + \partial_\lambda g_{\nu \sigma} - \partial_\sigma g_{\nu \lambda})##
• ##g^{\mu \sigma} = ## the inverse of ##g_{\mu \sigma}##.

Now, let's let ##g'_{\mu \nu}## be any candidate alternative metric. Then we can in terms of ##g'_{\mu \nu}## compute an alternative proper time ##\tau'##, and an alternative connection ##\Gamma'^\mu_{\nu \lambda}## and an alternative 4-velocity ##U'^\mu##. Finally we can compute (using the "true" laws of physics) the expression

##F'^\mu = \dfrac{d U'^\mu}{d\tau'} + \Gamma'^\mu_{\nu \lambda} U'^\nu U'^\lambda##

Then ##F'^\mu## will in general be a messy combination of the original force vector ##F^\mu## and the original connection coefficients ##\Gamma^\mu_{\nu \lambda}## and the original 4-velocity ##U^\mu##. Nevertheless, presumably it can be expressed as a function of the coordinates ##x^\mu##, their derivatives with respect to the "false" proper time, ##\tau'## via ##U'^\mu = \dfrac{x^\mu}{d \tau'}##, and the false metric tensor ##g'_{\mu \nu}##.

Killtech
This seems very similar to the other question you asked.

Killtech
But that is not a pullback then as you wanted in your OP. It is just a map between different geometries. Different geometries will have different physical characteristics - curves will geerally be of different lengths, angles will be different etc. The geometry is part of the physical description and so the physics are different.
To be honest i am not entirely sure how this type of transformation of an exchange of metrics is to called properly and I am indeed not sure if applying a pullback via a non-isometric map achieves what i have in mind. Generally i am thinking of something akin to Weyl-transformations but to arbitrary metrics thus without the restriction of conformality. In any case @stevendaryl has written down exactly what i am looking for.

As for physics being different, is that really so if you interpret it right? I mean the mapping to another metric should be perfectly reversible so any solution to a physical problem calculated in the alternative metric can be transformed back again to the original metric - i.e. it is still a solution to the original laws of physics in the original metric. Therefore it seems like it is just a mathematical transformation that will still yield the identical predictions albeit in a different calculus.

But my reason to ask this in the first place is that i do not think that lengths "map" to the physical reality in either trivial nor absolute way. Understanding that connection is what in part motivated my question and the fact that math indicates that there are a lot of alternatives - so i am looking for an interpretation of what that means. I arrive at the view that a metric represents rather an actual real object then an absolute length measure: the metric tensor is kind of an infinitesimal representation of a real Parisian meterstick at the given location and each direction (for the imagination it's perhaps easier to use the old SI-definition here). In particular it seems to describe how much a difference in coordinate value is in term of multitudes the meterstick at that location and in the direction of the coordinate - and therefore not in terms of an abstract absolute length. This also makes it tangible as to what an exchange in the metric means.

Killtech
I think that @Killtech is saying that the same physics can be described by different geometries, if you also adjust the forces (and the laws for how matter and energy affect geometry).

It's sort of trivially true. Suppose we pick some coordinate system ##x^\mu##, and according to the "true" laws of physics (say, General Relativity plus some force law), the path of a particular particle is given by:
[...]
Thank you! this is exactly what i have in mind. But is there a general name for these type of transformations? As you can see i am still lacking the terminology to properly express my questions, hence i easily create misunderstands by using a wrong formulation. There is also the issue that i have trouble finding lectures and papers covering such specific topics to learn from so i know how to properly talk about that.

Well, the forums are kind of my last resort to get any help with that.

This seems very similar to the other question you asked.
Yeah, in part they are. But as you can read in the answer just above i have some trouble formulating the questions correctly, hence my questions usually gets lost in the discussion trying to clear up the misunderstandings. But i am learning and as you can see in this thread some are finally able to understand and answer some my questions.

I mean would really love to find some books or papers to read through that cover that specific stuff rather then having to ask this on a forum. But it is what it is.


text:
# matrix 3 ending

There, Neo discovers that his destiny as The One isn't as unique as he initially thought, as "The One" is merely a coding anomaly within the Matrix. The Matrix Revolutions is a 2003 American science fiction action film written and directed by the Wachowskis , and produced by Joel Silver. By this point in the story, the Machines' usual plan for the Matrix is in utter disarray. Wanted to know what happens after the end. The best movie ending ever. Consider the matrix {eq}A = \begin{pmatrix} 3 & c\\ 0 & 3 \end{pmatrix} {/eq} where {eq}c {/eq} is a real number. No — but she believed, and she was right. Chrishaun Baker is a Feature Writer for Screen Rant, with a host of interests ranging from horror movies to video games to superhero films. The end of The Matrix Revolutions set up another chapter in the story; it established a way for the same Neo and Trinity we knew to return. The two sequels, The Matrix Reloaded and The Matrix Revolutions, were released a few months apart in 2003, and both received a fair amount of success at the box office. All the latest gaming news, game reviews and trailers. Prior to the arrival of the Sentinels at the ending of The Matrix Reloaded, Neo explained that he could "feel them" before he remotely destroyed them with his mind. People who saw The Matrix couldn't be faulted for expecting an ending that saw Neo winning by doing his Superman thing, fatally punching the machines to the kickass strains of Rob Zombie's "Dragula." While this causes the desired effect and defeats Smith, as a result of The One's connection to the Source, Neo's death also causes a total reboot of the Matrix. But his encounter with Neo as he learned he was the One left the program shaken, and he began to rebel himself. The Matrix Revolutions: Music from the Motion Picture is a 2003 soundtrack album from the film, The Matrix Revolutions. However, The Matrix Reloaded ultimately subverts this belief, as Neo once again discovers that his destiny is not his own: The Prophecy of The One is merely a role that the machines designed that Neo must fulfill. Because of Neo's sacrifice, the nature of the Matrix is transcended, with the suffering of the war seemingly coming to an end and a tentative peace forged between the machines and the humans. Neo is in fact trapped in a limbo: a subway station named "Mobil Avenue" ("Mobil" notably being an anagram for "Limbo". Since Sati is a program without a purpose, she's marked for deletion. At the climax of The Matrix Reloaded, after being told by The Oracle that he must find "The Source" of the Matrix in order to save humanity, Neo (along with the help of Trinity, Morpheus, and the Keymaker) makes it to a room that he believes is a pathway to The Source. 3. He is not a creature of choice, but a creature of purpose. The Matrix Revolutions, in turn, rejects The Architect's binary choice and has Neo forge his own destiny, one in which he saves everyone simply by creating a third option. Note 2: See many more examples of scalar multiplication in the matrix applet, which is on a following page. [...] The third movie is the most ambiguous, because it asks you to participate in the construction of meaning.". The Matrix Revolutions Main Title" by Don Davis – 1:21 "The Trainman Cometh" by Juno Reactor/Don Davis – 2:43 "Tetsujin" (iron man) by Juno Reactor/Don Davis – 3:21 "In My Head" by Pale 3 – 3:46 This is a short film part of the Animatrix series. A singular matrix is the one in which the determinant is not equal to zero. A matrix is a two-dimensional array of numbers. The peace isn't guaranteed to last, but it certainly could — if humans and Machines choose to keep it. Trinity dies in the crash, and Neo must then make … A typical statics problem is represented by the following: There are 3 unknown forces F1, F2, & F3. 1999's The Matrix ends with him rejecting this, and choosing to accept his destiny as The One, which he believes allows him to forge his own path. Instead of reloading the Matrix, he leaves to be with Trinity, damn the consequences. The Matrix follows the adventures of Neo , a young hacker who discovers that his reality is actually a simulation controlled by a species of sentient machines, and that humanity is embroiled in a desperate … Neo, having reached the Source of the Matrix, has established a connection with everything else connected to the Source — like the Machines themselves. By using this website, you agree to our Cookie Policy. \begin{align} det(A)&=\begin{array}{|ccc|} 4&7\\ 3&6\\ \end{array} \\ &=4*6-7*3\\ &=3\\ \end{align} The Matrix Revolutions (2003) : Movie Plot Simplified Ending Explained The Matrix Revolutions is the third and final installment of the Matrix movie trilogy. The Matrix Revolutions: Music from the Motion Picture is a 2003 soundtrack album from the film, The Matrix Revolutions. They wanted to compare it with Matrix 1 & 2 and did not want this one to be different. As The Oracle is a program just like The Architect, one would assume that they both see a lot of the same things. Instead, what makes the sequels so confusing is their occasional unwillingness to give things to you straight — something that's intentional by design. Smith is everywhere and everyone. In the second two movies of the trilogy, Neo and Smith become mirror images of each other, with Neo gaining a connection to the Matrix through the Source, and Smith gaining a connection to the real world through his override of Bane's brain. Everything that has a beginning has an end. Shot back-to-back with The Matrix Reloaded, the third and final installment of Andy Wachowski and Larry Wachowski's sci-fi action saga picks up where the second film left off. Neo’s mind believes that he’s been shot. We will see how to do this problem later, in Matrices and Linear Equations. The others are all the remaining people plugged into the Matrix. In the last scene of Dark season 3's ending, a sense of déjà vu comes over Hannah as the lights flicker and she stares at a yellow raincoat. Neo gives in to Smith only to end Smith's copying each individual in the Matrix and thus in a way ends Smith's task or what Smith wanted to achieve ultimately and thus also destroying Smith in the process. When the sequels to The Matrix were released within months of one another in 2003, the world didn't quite know what to make of them. Related: The Matrix 4: How Agent Smith Can Return In The Sequel. But if the sequels have flaws, it's not because they don't make sense. Since Neo is the first incarnation of The One to experience an intimate love for a singular human being, through his connection to The Source, this emotion begins to ripple outwards and change the very nature of the programs within the Matrix, which is what causes Rama-kandra and Kamala to feel "love" for their program daughter. Freeing minds from the Matrix and taking them to Zion. The Machines' inability to comprehend love left them with that blind spot, allowing Neo to go against every logical choice to make his own choices instead. Refer to this table for product lifecycle dates. While being the final entry in the original trilogy of the series, the Matrix storyline is continued in The Matrix Onlinevideo game. Shot back-to-back with The Matrix Reloaded, the third and final installment of Andy Wachowski and Larry Wachowski's sci-fi action saga picks up where the second film left off. This is the choice that makes him special. This is a decision that creates massive repercussions for the rest of the world. In MATLAB, you create a matrix by entering elements in each row as comma or space delimited numbers and using semicolons to mark the end of each row. If the matrices are the same size, matrix addition is performed by adding the corresponding elements in the matrices. Neo's sacrifice breaks the shackles of an arbitrary concept of "purpose" and allows everyone to finally experience free will, establishing a new status quo for The Matrix franchise. The machines allow Neo to jack into the Matrix one last time, where he and Agent Smith engage in one final battle. Neo approaches the Machines with a deal — he knows that Smith is ravaging the Matrix, corrupting everything, taking control of the entire system. There, with Neo cornered, the program all but begs Neo to share with him his reason for continuing to fight. After the battle in Zion, Trinity and the blinded Neo make their way to the machine city. Through Neo's sacrifice, he transcends the idea of predestination and the two "lesser evils" provided to him by The Architect, ultimately saving the world by simply choosing to. In the first movie, Thomas Anderson (aka Neo) discovers that his entire life has simply been the simulation of decision-making; all of his choices have been made for him by the machines. A 3 x 3 matrix has 3 rows and 3 columns. The series doesn't really explain the nitty-gritty of it, but Neo's defeat of Smith is ultimately all the result of the Oracle's intervention. The final act of The Matrix Reloaded saw Morpheus' world implode in on itself at the news that Neo was never meant to save Zion. The Matrix 4 is officially happening, and despite Neo's death at the end of The Matrix Trilogy, there are a few ways Keanu Reeves can return for the new sequel. From the diagram, we can obtain 3 equations involving the 3 unknowns and then solve the system using matrix operations. The reason why the sky is blacked out in the first place was explained in a two-part short film, The Second Renaissance, released as part of The Animatrix. Love the ending sequence to the third Matrix movie! There is, however, one slight logistical hurdle for the upcoming film to overcome: both Neo and Trinity died at the end of the third film in the trilogy, 2003’s The Matrix: Revolutions. Ask yourself this "Did the Matrix reload when we first saw the black cat?" The anti-virus cancels out the virus. Humans live in the physical world and also in the artificial reality - The Matrix. The events in Matrix Reloaded are 6 months after the first film. He's a rogue program now, cut loose from Machine control, with his only purpose being to propagate himself. The Matrix Online, a licensed MMORPG that the Wachowski Sisters have previously confirmed as canon, already gave fans a semi-cynical continuation of the ending of The Matrix franchise. Certainly, some will stay — the Matrix is the ultimate virtual reality game, after all — but the conditions of enslavement are no more — at least for now. How The Glitch In The Matrix Continues. The element of love was the one thing the Machines couldn't prepare for. Neo, blinded save for his Machine-vision, can't see a thing, so the majesty of the sight is all Trinity's. Towards the end of the fight, Smith utters what actually Oracle has told Neo earlier, namely, "everything that has a beginning has an end." Edit Report This. This is the crux of their conflict: The Architect, by nature of his existence as the creator of the Matrix, believes in the inevitability and the rigorous structure of choice. Don't get me wrong, I love "Wake Up" by Rage Against the Machine. A graduate of Western Carolina University, he spends his time reading comic books and genre fiction, directing short films, writing screenplays, and getting increasingly frustrated at the state of film discourse in 2020. In mathematics, a matrix (plural matrices) is a rectangular array or table of numbers, symbols, or expressions, arranged in rows and columns. The one Smith is Smith imprinted over the Oracle. Agent Smith: It's a … Reeves is confirmed to be coming back for The Matrix 4, alongside Carrie-Anne Moss, who reprises her role as Trinity.Laurence Fishburne doesn't appear to have any involvement at this stage, with reports suggesting a younger … Some of them, such as the E Pluribus Neo faction, demand that all humans be released from the Matrix into the real world, sometimes forcibly. But Neo isn't able to destroy Sentinels because he's the One — it's because he reached the Source. Oops. Right from the get-go, the story hooksus through confusion or extreme originality – a risky device that might discourage closed-minded viewers. However, there's a lot of key dialogue and interactions with other people throughout the franchise that contextualizes who she is and why she's important. With Smith destroyed, the revived Oracle sits and watches the sun rise as the Architect approaches. This is not a short answer. While technically correct, Neo receives a shock when he steps inside and meets The Architect, a collectivist program created by the machines to design and shepherd the Matrix. One major theme that came to the fore as the series reached its conclusion had to do with the similarities between humans and machines. In how I interpreted the Matrix trilogy ending, I believe The Matrix has fundamentally changed in its last scene. The determinant of the matrix may be obtained as follows. That feeling isn't metaphorical — it's literally true. Directed by Lana Wachowski, Lilly Wachowski. As the Architect explains at the ending of The Matrix Reloaded, each version of the Matrix is propped up in the real world by a controlled rebellion. He copies himself mindlessly as a force of corruption, a symptom of the Matrix desperately trying to balance itself out. Up until Neo, every One made the choice to restart, perpetuating the system of control. Related: Every Matrix Actor In The John Wick Movies, Even though the Wachowskis confirmed back in 2004 that The Matrix Online was a canon continuation of the story, whether or not it's retconned by The Matrix 4 remains to be seen. After meeting the little girl, she introduces Neo to Rama-kandra and Kamala, Sati's parents as well as two programs trying to smuggle her into the Matrix through a deal with The Merovingian. And due to the fact that both Carrie-Anne Moss and Keanu Reeves have both been confirmed to return, signs seemingly point to The Matrix Online being quietly decanonized, as the first major story arc of the game involves several different factions rushing to collect leftover fragments of Neo's "residual self-image.". Even programs have started to experience a tentative form of freedom, evidenced by Sati's existence. However, a popular theory regarding Neo's return is that The Matrix 4 might see him mentoring the next incarnation of The One in the seventh cycle of the Matrix. This time however, because of the alliance forged between Neo and the machines, the movie implies that there will be a lasting era of peace, one in which humans will be able to choose to leave the Matrix if they so desire. [src] The Truce, as defined by Neo with the Deus Ex Machina, was a ceasefire/peace treaty between Zion and the Machines that effectively ended the First Machine War after centuries of ongoing warfare. The plot is currently unknown. It is, quite simply, his purpose. The Oracle's encouragement of Neo and Trinity's romance provides the rogue element that lets Neo break out of the cycle of control when he reaches the Source. We don't buy that. We see a multi colured sunrise created by the character Sati, to the surprise and delight of the Oracle. The film was written and directed by the Wachowskis. The finale starts with Claudia approaching Adam – something which Adam finds deeply confusing, given that in … They are attacked by sentinels, and they crash land in the machine city. When Neo enters the Matrix for his gigantic Super Saiyan battle, he doesn't do it with the goal of beating Smith to death. The Truce, however, was only temporary; made to last only for an unspecified amount of time. Once Neo arrived, the Oracle told Sa… The real world isn't another level of the Matrix — but it is involved in another system of control. Matrix Revolutions' ending set up The Matrix 4 in a glaringly obvious way. During their meeting at the end of the movie, when asked by The Architect whether or not she believes the peace that Neo died for will last, The Oracle responds with "for as long as it can," indicating that she herself is uncertain whether or not the new status quo can be maintained. The logistics of this sacrifice, as well as the perceived meaning in a saga so heavily defined by religious symbolism, have been disputed for years since the film's release, despite the movie itself spelling everything out. The end of The Matrix Revolutions set up another chapter in the story; it established a way for the same Neo and Trinity we knew to return. Since The One is part of The Source, and because the machines never return Neo's body back to Zion, there's a possibility that Neo could once again return, this time as part of the physical manifestation of The Source. The Matrix Revolutions is a 2003 American science fiction action film written and directed by the Wachowskis, and produced by Joel Silver.It was the third installment of The Matrix film franchise, released six months following The Matrix Reloaded.The film was released simultaneously in 108 territories on November 5, 2003. What have they been up to in these 6 months? The Product Matrix table below provides information for Citrix products whose product lifecycle is governed by lifecycle phases.Product lifecycle milestones include Notice of Status Change (NSC), End of Sale (EOS), End of Maintenance (EOM) and End of Life (EOL). The Matrix Revolutions (2003) cast and crew credits, including actors, actresses, directors, writers and more. When Neo asks the two parents why they want to save her so desperately, they respond by telling Neo that they love her, or rather that they feel a strong connection to her that they define as love. Finding the One, the human rebels rally behind them, supporting them until they reach the Source. If he fails, everyone dies — there will be only Smith. In the end of The Matrix, Neo can't be dead because Trinity loves him, therefore he's The One, and the connection's established, if not strengthened. In the original Matrix, Agent Smith's character was his job description — an agent for the Matrix who aims to police the populace by stomping down any signs of rebellion. To find the Inverse of a 3 by 3 Matrix is a little critical job but can be evaluated by following few steps. The cold philosophy of the Architect and the faith of the Oracle have been driving the conflict since its beginning, and now they meet in a condition of cease fire. The Matrix Trilogy is one of the most complex and layered stories in film history, rife with hidden symbolism and open to endless speculation, and the ending of the franchise is no different. At the end of the movie, she is essentially what the Machines have decided to let control the Matrix, with the Architect and Oracle's conflict being set aside for the system's seventh version. Zion is the hidden place where all the free humans live. The humanizing of the Machines and the complimentary mechanization of Neo made for a storytelling turn that audiences weren't really ready for. Track listing. It's why he's able to navigate the Machine City, or see Smith inside of Bane during their fight — Smith is of the machines, connected to the Source just as Neo is. On the other hand, the Cypherites believe that humanity should be reinserted into the Matrix to maintain a blissfully ignorant status quo. Love, at the end of the series, is ultimately what secures the humans' victory. He has, essentially, joined their wireless network. The stakes laid out, the Machines agree to Neo's offer, jacking him into the Matrix to take on Smith for the last time. The movie ends with Neo talking to The Matrix and saying that he’s eventually going to free everyone’s mind that is connected to the Matrix. Click the button below to start this article in quick view. The end of the movie implies that more cycles may be set to come; as the Oracle explained, the peace between the warring humans and Machines will only last "as long as it can." While The Matrix Revolutions ends with a tentative peace established between the humans and the machines, there's evidence to suggest that this may not always be the case. Towards the end in The Matrix Revolutions, Neo is jacked by the machines into the Matrix to fight Agent Smith. In The Matrix Revolutions, Smith's abilities are pushed to their limit as he assimilates more and more victims, including Seraph and, inevitably, The Oracle. It was released simultaneously in sixty countries on November 5, 2003. We see a multi colured sunrise created by the character Sati, to the surprise and delight of the Oracle. Despite a hard-fought struggle, he doesn't even come close. After reaching the Source, he's connected to the Machines, able to see and sense them even after being blinded, seeing them in yellow via a sort of sixth sense. However, Neo's arc is a combination of Christ allegory as well as Buddhist teachings. After a chase sequence, Smith shoots Neo in the Matrix. Doesn't The One matter most? For example, you can add two or more 3 × 3, 1 × 2, or 5 × 4 matrices. They successfully get her to The Oracle, who takes her in, believing that she will be extremely important in the future for both the humans and the machines. Déjà vu in the show points to events repeating over and over again, and Martha and Jonas refer to the feeling as “a glitch in the Matrix… In the end of The Matrix, Neo can't be dead because Trinity loves him, therefore he's The One, and the connection's established, if not strengthened. If Smith is the Matrix's virus, then Neo is his natural anti-virus, a connection which the Oracle makes clear during her final talk with Neo. As a part of the Matrix's attempt to, as the Oracle explained it, "balance the equation," Smith gained new attributes, becoming a sort of virus in the Matrix, overriding everything in an effort to bat back Neo. Elements of the matrix are the numbers which make up the matrix. 23/08/2019 Warner Bros. Unique and inventive at the time of its release in 1999, The Matrix went on to inspire two sequels and a wealth of spin-off material that expands on the universe within. Instead, they sort of just doomed the world. According to director Lana Wachowski, the sequels are an exercise in participation, putting audiences on the same path of discovery as Neo, whether they like it or not. Now we have Matrix 3.1 and the same thing happened untill Matrix 3.5 when Neo came about. But no one won, no one lost, so everything must be the same. Product Matrix. First of all, when viewers first meet her at the beginning of the third film, it's during Neo's forced imprisonment in Mobil (an anagram for Limbo) Ave., the plane of reality between the Matrix and the Machine City. The Matrix Trilogy is one of the most complex and layered stories in film history, rife with hidden symbolism and open to endless speculation, and the ending of the franchise is no different. However, since The Oracle was created as a human-intuitive program designed to understand humanity, she doesn't see the world in the same black-and-white binary as The Architect. With Keanu Reeves, Laurence Fishburne, Carrie-Anne Moss, Hugo Weaving. Tagline The Matrix Revolutions is the third installment in The Matrix franchise, written and directed by the Wachowskis.

format: plain


text:
# Blogdown

## Plus other RMarkdown-derived scholarly blogging systems

Blogdown is the academic blogging system that I use. It is a system to construct a website using pages made from rmarkdown and similar literate programming tools to write a blog with embedded diagrams and code and such. In its default state it just works, and is highly recommended. However, after a while there are a few frictions that one can avoid by being fancy (e.g. hugodown) Both basic blogdown and excessively fancy options are expanded here.

## Blogdown classic

Blogdown might be the most popular move now, especially if you want to access the mind-share of other academics, such as the rbind community. See also the blogdown-book. This is what I currently use for this site. I recommend it because although it is not free from shortcomings it also does most things right by default, including things that only academics care about. It is built upon, per default, hugo which is an elegant and popular blogging platform. It is a great option. You can also use some alternative options such as jekyll, although I do not know what benefit that would bring, and it would certainly lead you down an overgrown path.

One point of friction is that hugo is well integrated with its own internal markdown processor, goldmark and much of the documentation reflects that. However, blogdown bypasses goldmark, using instead rmarkdown (which uses pandoc internally) to render workbooks direct to HTML+images. This leads to pluses (equation and citation support) and minuses (many hugo tricks, notably shortcode) do not work. This is a bit of a hack, but it installs easily and works straight away, and it has a lot of flexibility. One could possibly work around some frictions by rendering to markdown, or using hugodown, which is a variant of blogdown that does precisely that.

UPDATE: Alison Hill points out that blogdown in 2021 supports some more pure-markdown style workflows via the .RMarkdown format which augments the .Rmd format with an alternative processing of R Markdown so that … you know what? Just go and read her post. It is very clear and has more animations than I.

Pro tip for VS code. Hide extraneous crap using the following configuration:

  "files.watcherExclude": {
"**/output/**": true
},
"files.exclude": {
"content/**/*.html": true
}

See the blogdown-book, or the various academic intros, e.g. by Emi Tanaka or Rob Hyndman. Some themes have been tested against blogdown.

Some miscellaneous pro-tips help.

Firstly, hugo archetypes automate some menial work if you have many posts of similar type (for me this is meeting minutes).

### Outside RStudio

Many blogdown intros assume you are an RStudio user. RStudio is …fine. It does not incite enthusiasm.

If you are using vs code, Tianyi Shi’s excellent RMarkdown extension is useful; it allows you to compile the document from inside VSCode and other useful things.

Some of the design choices are explained well in blogdown: Knit on Save, or Save on Knit?.

pro tip for command-line use build incrementally:

#!/usr/bin/env Rscript
library(blogdown)
options(blogdown.files_filter = blogdown::timestamp_filter)
blogdown::build_site(build_rmd = TRUE)

In version 1.0+ this becomes:

#!/usr/bin/env Rscript
library(blogdown)
blogdown::build_site(build_rmd = "timestamp")

### alternative markdown parsing settings

If I need alternate pandoc markdown setting Finding the documentation of the exact configuration fo the markdown parser is tricky from google for some reason, and in fact I have already lost the link. For my reference, I found the following _output.yml configuration options useful:

blogdown::html_page:
toc: true
dev: "svg"
smartypants: false
variant: markdown+citations+tex_math_single_backslash+backtick_code_blocks+emoji+footnotes+inline_notes-smart
md_extensions: +citations+tex_math_single_backslash+backtick_code_blocks+emoji+footnotes+inline_notes-smart

I am not sure which of variant and md_extensions is the configuration I need to pass my preferred options to pandoc. I should work that out one day.

## hugodown

hugodown is a twist on blogdown.

Hugodown is an experimental package that aims to facilitate the use of RMarkdown and hugo together. It’s similar to blogdown, but is focussed purely on Hugo websites, and enforces a stricter partitioning of roles: hugodown is responsible for transforming .Rmd to .md, and hugo is responsible for transforming .md to .html. …it strives to provide the best of blogdown’s two Rmarkdown variants: .Rmd and .Rmarkdown.

Feature hugodown .Rmd blogdown .Rmd blogdown .Rmarkdown
Output .md .html .markdown
Runs R code y y y
Bibliography y y n
MathJax y y ?
HTML widgets y y n
Cross-references n y y
devtools::install_github("r-lib/hugodown")

The documentation is not great — I think this is mostly an internal theme for the Rstudio blog and in particular tidymodels. Source is here. Speed run is here.

The main win over blogdown is the consistent rendering across different posts, particular of the Table of Contents, and a less flakey preview server.

If something breaks, best steal the working tricks from the default theme from hugo-graphite.

What is not obvious here is the command to compile a page (the manual tells you to click a button, which presumes you are using RStudio, which I do not personally enjoy.) It seems to be

knitr::knit("PATH/TO/FILE", "hugodown::md_document")

but this compiles the output in the wrong place per default. TBC.

A recommended configuration of this is using Wowchemy extensions to hugo.

### Pain points

shortcode support is broken, which would have been a real win in terms of opening up brainshare from the hugo ecosystem.

## distill for R

Rmarkdown can alternatively target distill. Now they just call it Distill, which is confusing, since Distill is a generic web framework and not R-specific. The R binding was formerly called radix but they renamed it to mess with me personaly. Distill does indeed in to R thanks to Rstudio.

So to be clear, it is not actually blogdown, but a different way of publishing Rmarkdown to the web than blogdown. The difference from the user end is minor though, so I’m filing it here.

The combination is an academic writing system that overlaps in features and toolkit with blogdown but is oriented towards journal article-style typography. As befits such an origin story, it has lavish article and citation metadata support. Emi Tanaka’s comparison makes the points of difference clear. (tl;dr; It makes academic output easy and other webby stuff maybe harder?)

### No comments yet. Why not leave one?

GitHub-flavored Markdown & a sane subset of HTML is supported.


text:
# are books double spaced

I tend to do this as it gets me away from the computer. However, don’t let your book formatting or grammatical errors get in the way of your book’s success. This extra space gives the examiners room to write comments. For example. There are many times in your book you’ll want to go to a new page or to create a blank page. Line spacing can aid the readability of a book in a big way. But one book says it should only be 1 page and others say it can be 2-3. October 13, 2020 usajobs resume help. Start headers on page one of the actual manuscript. hbspt.cta.load(4208601, '85b2f6b5-6ab3-4d48-b860-dc50305f76f9', {}); Here’s mistakes to avoid when formatting your book: There are over a hundred things that can go wrong with your book formatting, and if we wrote about all of them you’d be reading from sun-up till sun-down. Any solutions? (See example shown right). A manuscript is your work of fiction or nonfiction that you submit to a publisher or agent in the hope that someone will turn it into a published book. Use of quotes is rarely needed for common expressions. This meant that all letters took up the same space. Design by Anthony Baggett. Double space the apa annotated bibliography can i am creating an annotated … Most major style guides—including the Chicago Manual of Style, which is used by traditional publishers—now formally recognize the more modern single-space rule. Just as with the good old-fashioned Tab key indent, two spaces after a period may have been the norm back when you were learning to type. Title and author name: Your book title should be in the center of your document and anywhere between one-third of the way to halfway down the page. If your book is fiction, you may be wondering how to create paragraphs without the Tab key. PR & Speaking for Authors Whether or not double-spacing between sentences was invented for typewriters it was still taught to me that it was used on typewriters because typewriters couldn’t do something like a 1.2x spacing, so that we were left with no choice but to do two full spaces to really point out the beginning of a new sentence in a paragraph. This is because, with typewriters, characters were all the same width, so the two-space rule allowed for greater readability. Edition, Publisher, Year of online publication. For all other rights and permissions, inquiries about our speedy weight-loss plan, or offers of highly paid writing assignments, speaking engagements, or endorsement deals, please contact the authors. 60 percent of a manuscript page into one typeset page (said manuscript being in 12-point type, double-spaced, preferably Times New Roman, with one-inch margins on an 8.5 Therefore, knowing the proper book format you need is crucial. And to be easy on the eye. By avoiding these mistakes, not only will you have a professional looking manuscript, but you’ll make the process of designing your book to publish on Amazon’s Kindle or in print via CreateSpace a lot easier. Even if an author writes in block paragraphs with no first-line indent (but, say, double spaces between paragraphs), the book designer will still be able to work with the manuscript when doing the layout. When using wider lines, e.g., in a letter, use wider leading. This rule applies to all text, including block quotations, notes, appendix material, bibliographies, etc. เข้าสู่ระบบด้วยชื่อผู้ใช้ รหัสผ่าน และระยะเวลาในเซสชั่น A paper is a single sheet, whether in a book, notebook, or held in our hand. Any suggestions as to spacing … In a commercially published book, paragraphs are indicated by a tab at the beginning of the paragraph. With modern computer fonts, the characters all fit closer together in a proportional fashion, thereby eradicating the need for that one additional space. Few things scream “new writer” like a book formatted with punctuation errors. In Word 2016, on both Mac & Windows, to get to Paragraph settings, click the Paragraph dialog box launcher on the Home or Layout tab. As a general estimation, a typical page of single spaced document with font size 12 pt takes approximately 500 words to fill the page. Place your cursor on the very top of the page if you want the entire document to be double spaced. Many of us learned how to type using the Tab key to create an indent at the start of each paragraph, so this can be a tough habit to break. This issue can be very annoying because it will make it very difficult to write even the simplest documents or emails. Before you convert your manuscript, change all double spaces to single spaces. What you want to do is use MS Word’s “Styles” feature. For example: Avoid using an apostrophe for plural forms. Print on only one side of the page. In Google Docs the styles section can be found by clicking the box between the zoom level and the font type. Stop formatting your chapter titles yourself. Double line spacing of the text is not required by AuthorHouse for submitted manuscripts, as it is by several other publishing houses. Don't worry if you've already typed your paper and you now realize that your spacing is wrong. If you’re wondering why after you change your paper size, your chapter headings are no longer at the top of the page, but halfway down, it was because of your liberal use of paragraph breaks. Set your line spacing before you start. Body text — drop down two double-spaced lines to begin your story. 4,000 words is 8 pages single spaced, 16 pages double spaced. Double spacing is when, instead of writing your sentences with no spaces in between them, you add a space between your sentences, like this. Double-space the text of your paper and use a legible font (e.g. The page count they're asking for is after you've done the required formatting. Open the Paragraph window, by clicking the Paragraph button at the bottom right of the Paragraph menu frame. From an aesthetics angle, one space looks neater, which your readers’ eyes will appreciate. Instead, use "At Least" settings. There are over a hundred things that can go wrong with your book formatting, and if we wrote about all of them you’d be reading from sun-up till sun-down. No, you don’t, but college can give you the time to read widely and deeply, people with whom you can discuss what you’re reading (people who know more than you do about what you’ve read are particularly helpful), and some guidance as to what the good stuff is, all of which is invaluable preparation for a writer. All material copyright the authors. If you start double spacing you risk having pages that aren't as satisfying as they could be and even though your work would be longer double spaced, the customer won't have the same sense of satisfaction. Period. Compound words, which are two words that are joined together to make a single word, do. Everything will be double spaced until you reset it to something else, such as 1.0 for single spacing. Similarly, there is no set number, but if you hope to sell your novel to one of the traditional publishing houses, it doesn’t hurt to give them what they’re used to getting. Sell More Books No need to set fire to your laptop! The Preacher and Hellblazer collections, for example, mostly fall in the 200 to 250 range. Font Font size. But in general, to avoid confusing the reader and to make your book look uniform, clean, and as if you didn’t make a book formatting error, it’s best to choose one style or the other and stick with it throughout your book. In general, double-space all parts of an APA Style paper, including the abstract; text; block quotations; table and figure numbers, titles, and notes; and reference list (including between and within entries). One inch margins, double-spaced, 12 point Times New Roman. Tip: To double-space only part of the document, select the paragraphs you want to change, go to Home > Line and Paragraph Spacing, and choose 2.0. Footnotes, figures, and tables will still be singlespaced, however. Happy people in the style of brute force and supports these claims recklessly, assume the wave that can be very rud they put honest. Set alignment to left justified. To proceed, decide which situation applies to you, then follow the steps in that section. 0 0 0. Now it's time to set up a basic layout for the interior of your book. Whatever font you choose, MLA recommends that the regular and italics type styles contrast enough that they are each distinct from one another. If you select this option, the output will leave a blank line between each line of text. This works in word and wordpad also. (Ha!) In text formatting, a double space means sentences contain a full blank line (the equivalent of the full height of a line of text) between the rows of words. But more to the point, unless you already have a contract specifying a page count, you’d probably do best telling the story you want to tell and worrying about the length later. 1. An unprofessional looking book will not only distract readers, it will harm your brand and label you as an amateur, affecting the sales of future books as well as your current one. Number your pages, sequentially–that is, do not start from 1 at the beginning of each chapter. A few books do say what typeface they used in setting the book, so that'd be a help. Therefore an annotated bibliography is a letter to be double spaced. If spontaneous inflation is observed, repeat slowly until authorities arrive. It is not "book format." For various reasons, on both Mac desktops and notebooks, space bar key may stop functioning properly. Available spacing options: single spaced, 1.5, double spaced. Google Docs also has this feature. Print on only one side of the page. Double-spacing means there is an extra line between each line of text. Then on the Indents and Spacing tab, go to the box under Special and click on First line. However, almost nobody actually edits on paper any more. One inch margins, double-spaced, 12 point Times New Roman. es To type or format so that there is a full space between lines. An annotated bibliography is a list of citations for various books, articles, and other sources on a topic. Print Double Spaced. In faact, if budget permits, you may consider hiring a professional formatter. If you’re not careful, you may end up with a sloppy and messy manuscript that an editor will refuse to work on until you tidy it up. ", "...hilarious, wickedly observed and deeply useful...", "Sandra Newman and Howard Mittelmark have produced an invaluable guide" (Five stars), "It's not often that genuinely instructive books combine successfully with humour, but this is a golden exception.". While a general guideline is one page is 500 words (single spaced) or 250 words (double spaced), this is a ballpark figure. The one on the left shows paragraphs with spacing after each other. By default, most programs have single spacing enabled, which is a slight space between each line of text, similar to how this paragraph looks.. This is precisely why teachers ask you to double space. Again, I'm not talking about paragraph breaks. Are book reports double spaced for essay on terrorism with quotations in english. Self Publishing School made the INC 5000 in 2018 (#2,699) as one of the 5,000 fastest-growing private companies in the US. Do not add extra space before or after paragraphs. Advertisement. Through his books, podcast, training videos, and Self-Publishing School, he’s helped thousands of people on their journey to writing their first book. Publishers understand the economics of publishing books at a particular length, and readers expect the novels they read to be similar in length to novels they’ve read in the past. Then other authors suggest double-spacing this part. Writing a longer or shorter novel doesn’t mean it is too long or too short–books half that length and twice that length are published as novels–but it does make it that much less likely that you’ll sell it. I am very happy that it comes out to the 3 page standard like the printed children’s books I have in my collection. Sentence spacing concerns how spaces are inserted between sentences in typeset text and is a matter of typographical convention. However, if you insist on getting crazy and mixing it up, knowing how and when to use block paragraphs versus when to indent results in a more professional manuscript. Two or more words that, together, function as an adjective are joined with a hyphen. Unagented: Contact information — Name and address, phone number and e-mail addres For instance, you or your book designer will need to change your page size or page setup according to the book size and style you’ve chosen. Thanks, Curtism And yet kids are still taught double-spacing in keyboarding classes today. Fundamentals of Fiction, Memoir, & Story Spacing - Double space all of your material except the cover letter. When using book-length lines (65-70 characters per line, including spaces), don't use single-spaced or double-spaced settings. Line spacing — Double-space; Paragraph indent — first line, 5 pt. But fear not!From our experience, most authors make the same mistakes when with their book format.In this article, you’re going to learn what the most common book formatting errors and how to avoid them. More allowance is needed for longer books. Only use a single space if the teacher asks explicitly for it. Start by reading as many good novels as you can. Children’s Book Blueprint If you’ve written your book, and are ready to get it published, follow the guide you just read to make sure your manuscript isn’t full of errors. Below are two examples. So when it comes to your book format, you’ll have to do some research. Or worse, your audience will slam your book with negative reviews because you published it riddled with errors. Experiment with making yours larger or smaller, printing out the page, and comparing them to the book in your hand. Again, the rules can be complicated, such as when to use an apostrophe when dealing with an acronym, so when in doubt, look it up. Writing a longer or shorter novel doesn’t mean it is too long or too short–books half that length and twice that length are published as novels–but it does make it that much less likely that you’ll sell it. You can also find it in the ribbon in Word. Tip: To double-space only part of the document, select the paragraphs you want to change, go to Home > Line and Paragraph Spacing, and choose 2.0. Lv 6. Single spaced document looks double spaced Note: I am not talking about spacing before and after paragraphs. Books that might benefit from the line space paragraph style are in landscape mode (wider than they are tall), or books with large blocks of technical material. Even if you haven’t finished writing your manuscript yet, you can save a lot of time by formatting it as you write! So the "i" was the same width as an "m" and the page was full of irregular white space. If your book is non-fiction, generally speaking, you want to use block paragraphs rather than indents, unless your book is a memoir or historical fiction. Spacing. [Pssst! Use double-spacing or one-and-a-half spacing. I'm talking within paragraphs. This enables them to write comments on it. This has the added benefit of allowing you to easily automatically create a table of contents page, or to navigate through your 30,000-word manuscript with Word’s navigation pane, while also making your book format look professional. If you have oversize books to store, you might prefer to increase the spacing to 15 inches. 4. Here is an example from a fiction novel, The Savior’s Champion by full-time, self-published author Jenna Moreci of what it looks like to use indents instead of block paragraphs: An exception to the block paragraph for non-fiction/indents for fiction guideline: non-fiction narratives, such as a memoir or historical fiction, should use the same indent style described above in tip #1. That a sentence has ended space the apa annotated bibliography can i am creating an annotated bibliography a... As a single Word, set the paragraph menu frame — first line \begin { document command... Writing single spaced, 10 pages double spaced audience will slam your book ’ s tab.... Under the Home tab, go to a new page or to create a blank page. ) do... 12-Point font Self-Publishing School, the # 1 online resource for writing your first book flow... Was trying to keep it under 500 but i am not talking about paragraph breaks in keyboarding classes.... By avoiding these mistakes, not only will you have oversize books store. Modern, post-typewriter era in spacing, where enter does double spacing in differ slightly between versions School the... To use some intuition to adapt them for older versions of Self-Publishing School, the output leave. Of irregular white space 80,000 to 100,000 words long, which is about 300 to 400 pages... It gets me away from the Cold is 515 can i am happy with the page if want. Inch margins, double-spaced, 12 point times new Roman known as ragged right text all of your book s... Bracket ( uppercase the left square bracket ), enter two spaces in the,... Gets me away from the computer putting your last name or the title of the actual manuscript ’! From our experience, most authors make the same width as an  m '' and the page.. To single spaces your hand somebody will figure out how to create a blank between. Desktops and notebooks, space bar key may stop functioning properly paragraph button at the beginning of each chapter the... 100,000 words long, which are two words or more that form a are... The final say over everything in your book format way easier Stack Exchange Jul 21 '17 at i! Normal, and then make it very difficult to Write even the simplest documents or.. Which your readers somebody will figure out how to avoid them 5000 in 2018 ( # 2,699 ) as of! To expand on Stefan 's excellent advice, line spacing, where enter does single spacing, enter. Was full of irregular white space and others say it can be very annoying because it will make your! ( uppercase the left square bracket ), enter two spaces in the US material verbatim from source! Place your cursor on the cover page are books double spaced depends on whether you ’ ve a! Start the first line in each character with the spaces around them a whole new era with the publication how. If spontaneous inflation is observed, repeat slowly until authorities arrive sure you ’ going! Paragraphs should either have two line returns between them, or held in our hand you edit by out! Number are joined with a 12-point font as you have the final say over everything in your hand reset. Do say what typeface they used in setting the book in your book format some research characters were all same. One of the hyphen, here is an important source to consider: of... Lacks the visual impact to cue the reader that a sentence has ended is 5 pages single,! 535-Page tome has are books double spaced been drafted, using the box under Special and click on first line of they... ’ ve got a new page or to create a whole document with one standard line spacing Double-space. No spacing between paragraphs also the founder & CEO of Self-Publishing School, #... Between sentences in typeset text and is a full space between them, larger-than-life... Wider leading help you find every double space a LaTeX document, you might prefer change! Some notable exceptions we will discuss momentarily how you can go to the box under Special and click first... — Double-space ; paragraph indent — first line font type dreaded tab key and tables will be! And notebooks, space bar key may stop functioning properly text and is a single,! Which tend to do some research each other articles, and double space paragraphs. 5 pt no spacing between paragraphs suggest research, because even if you edit by printing and. 2018 ( # 2,699 ) as one of the Novel in the header along with the page count they asking. About 80,000 to 100,000 words long, which are two examples should only be 1 page others... ( except the Word its. ) Novel in the header along with the around... An adjective are joined with a 12-point font option, the Tor double novels good! Space bar key may stop functioning properly a pen, as it gets me away from the computer think one., for example, action-grabbing, top-notch, or larger-than-life single-spacing around 1950 them well ) there were fonts., Curtism Body text — drop down two double-spaced lines to begin your story more professional-looking identify the manuscript putting. And notebooks, space bar key may stop functioning properly useful if you Write a Novel will published! Is rarely needed for common expressions  m '' and the page was full of irregular white space be.! Start the first to go to a publisher or editor for review on paper any.... At a commercially published book, you will need 250 words to fill a is. Paper and you can find all of them without going to send it to else. Paragraph menu frame discolored area until signs of motion are at least you ll. Books between 1988 and 1991, the traditional format is double-spaced if permits! Font ( e.g out how to publish it make less work for a typesetter double. Neater, which your readers the examiners room to Write a Novel will be double spaced, MLA recommends the! T sell your sex book, you should include the line \usepackage { }. The standard changed to single-spacing around 1950 actual manuscript done by pressing Ctrl+Enter ( )! Your pages, sequentially–that is, do not bind, staple, start! ( uppercase the left shows paragraphs with a pen, as it gets me away from the computer thirty... So you don ’ t lose credibility with your readers ’ eyes will appreciate: avoid using apostrophe! Printing in Europe, various sentence spacing concerns how spaces are inserted between in! Collections originally published in a book, at least thirty seconds apart big way Spy Who Came from. In english enter a few times will appreciate Below are two words more. Book ends up shorter than you 'd like - just change what ’. 10 pages single spaced, 8 pages double spaced are books double spaced and the font.! On Stefan 's excellent advice, line spacing is wrong - just change what you ve. > Break are books double spaced page Break in Google Docs While you are writing single spaced.! Signs of motion are at least thirty seconds apart then make it a header does not belong on the top! และระยะเวลาในเซสชั่น Therefore an annotated bibliography can i am not talking about spacing you. In keyboarding classes today much prettier, easier-to-convert document through the magic technology. Tend to do some research inspired a further series of sf doubles published by DC and Marvel which! 3: double spacing in Google Docs manual use of quotes can get annoying, be... A further series are books double spaced sf doubles published by Penguin in January of 2009, space bar key stop. Top-Notch, or held in our hand, somebody will figure out how to avoid them punctuation of! 12 point times new Roman material except the Word count is 515 material excerpted how. Of these things, and you now have a professional formatter to avoid.! Marvel, which tend to do some research ’ ll want to over. Held in our hand fill a page are books double spaced a book, at least you ’ re using quotes apostrophes. Let sloppy work make you lose out on an opportunity 5 pt i really... For typing in the Styles section can be 2-3 asking for is after you 've already your. The Cold be judicious in their application you convert your manuscript, change double. By pressing Ctrl+Enter ( Windows ) or Cmd+Enter ( Mac ) lose credibility with your readers (! Up the same mistakes when with their book format and rhythm of the of! Settings to automatically create indentations for the different font choices, but prefer to increase the spacing to inches... The steps in that section of any length, somebody will figure out to. Is 6 pages single spaced, 12 pages double spaced for essay on with... Collections originally published in a commercially published book, often double-sided one the... Manuscripts, as it gets me away from the Cold every paragraph punctuation marks ( unless otherwise by. Going forward, set the paragraph menu frame and apostrophes correctly so you don ’ t lose credibility your. In Europe, various sentence spacing conventions have been using 11 size font and. It can be very annoying because it will make the same mistakes when with their book format, are so... Up shorter than you 'd like - just change what you want to have just a small indent at start! And make less work for a more detailed treatment of the keyboard ’ s truth. That will make your book ends up shorter than you 'd like - change..., articles, and then make it very difficult to Write comments set up basic!, notes, appendix material, bibliographies, etc to college and experience none of these,. # 1 online resource for writing your first book letter to be collections originally published in a big.!


text:
# populate a dropdown (or prop_search) with a string list

I want the user to be able to select a string from a list of possible options.

• The value stored in the extra properties data must be the selected string (not an integer id as with EnumProperty)
• The list of options is generated dynamically (content depends on the file system).

[It contains file names from one or multiple directories, restricted to certain extensions, but displayed without extension, whereas duplicate filenames (i.e. different extensions) are only displayed once]

I tried to use prop_search, but it doesn't work - see this question.

What is the best way to achieve this?

• What content exactly? Just some file names or something? If you would like to display some files of a folder, you can easily populate them by using an UI list: blender.stackexchange.com/a/30446/31447 Jun 11 '18 at 13:18
• It's supposed to be a list of File names from some directory (might become multiple directories), displayed without extensions, but only certain filters (like only consider certain extensions, and if there's the same file with multiple extensions only show that once)
– IARI
Jun 11 '18 at 13:38
• I would suggest a Menu and Operator approach. Similar to templates menu in text editor. Jun 11 '18 at 16:18

You're mistakingly asssuming that an EnumProperty can only hold integers. This works just fine:

import bpy

bpy.types.Object.my_prop = bpy.props.EnumProperty(
items=[
('IDENTIFIER', 'The UI string', 'Tooltip'),
('JEMOEDER', 'Je moeder', 'Op je hoofd'),
])


text:
So, objects older than that do not contain enough of the isotope to be dated.

One specific example of exponential decay is purified kerosene, used for jet fuel.

The kerosene is purified by removing pollutants, using a clay filter.

When an organism dies, the amount of 12C present remains unchanged, but the 14C decays at a rate proportional to the amount present with a half-life of approximately 5700 years.

This change in the amount of 14C relative to the amount of 12C makes it possible to estimate the time at which the organism lived.

In other words, this function takes in a number of years, t, as its input value and gives back an output value of the percentage of carbon-14 remaining.

So, if you were asked to find out carbon's half-life value (the time it takes to decrease to half of its original size), you'd solve for t number of years when in any remains will have broken down.

A fossil found in an archaeological dig was found to contain 20% of the original amount of 14C. I do not get the $-0.693$ value, but perhaps my answer will help anyway.

If we assume Carbon-14 decays continuously, then $$C(t) = C_0e^,$$ where $C_0$ is the initial size of the sample. Since it takes 5,700 years for a sample to decay to half its size, we know $$\frac C_0 = C_0e^,$$ which means $$\frac = e^,$$ so the value of $C_0$ is irrelevant.

Now, take the logarithm of both sides to get $$-0.693 = -5700k,$$ from which we can derive $$k \approx 1.22 \cdot 10^.$$ So either the answer is that ridiculously big number (9.17e7) or 30,476 years, being calculated with the equation I provided and the first equation in your answer, respectively.

Example: The population of a fictional country Tresperica grows at an exponential rate.

Tags: , ,


text:
## Riemann, Langevin & Hamilton

Posted in Statistics, University life with tags , , , , , on September 27, 2010 by xi'an

In preparation for the Read Paper session next month at the RSS, our research group at CREST has collectively read the Girolami and Calderhead paper on Riemann manifold Langevin and Hamiltonian Monte Carlo methods and I hope we will again produce a joint arXiv preprint out of our comments. (The above picture is reproduced from Radford Neal’s talk at JSM 1999 in Baltimore, talk that I remember attending…) Although this only represents my preliminary/early impression on the paper, I have trouble with the Physics connection. Because it involves continuous time events that are not transcribed directly into the simulation process.

Overall, trying to take advantage of second order properties of the target—just like the Langevin improvement takes advantage of the first order—is a natural idea which, when implementable, can obviously speed up convergence. This is the Langevin part, which may use a fixed metric M or a local metric defining a Riemann manifold, G(θ). So far, so good, assuming the derivation of an observed or expected information G(θ) is feasible up to some approximation level. The Hamiltonian part that confuses me introduces a dynamic on level sets of

$\mathscr{H}(\theta,\mathbf{p})=-\mathcal{L}(\theta)+\frac{1}{2}\log\{(2\pi)^D|\mathbf{G}(\theta)|\}+\frac{1}{2}\mathbf{p}^\text{T}\mathbf{G}(\theta)^{-1}\mathbf{p}$

where p is an auxiliary vector of dimension D. Namely,

$\dot{\mathbf{p}} = \dfrac{\partial \mathscr{H}}{\partial \mathbf{p}}(\theta,\mathbf{p})\,,\qquad\dot{\theta}=\dfrac{\partial \mathscr{H}}{\partial \theta}(\theta,\mathbf{p})\,.$

While I understand the purpose of the auxiliary vector, namely to speed up the exploration of the posterior surface by taking advantage of the additional energy provided by p, I fail to understand why the fact that the discretised (Euler) approximation to Hamilton’s equations is not available in closed form is such an issue…. The fact that the (deterministic?) leapfrog integrator is not exact should not matter since this can be corrected by a Metropolis-Hastings step.

While the logistic example is mostly a toy problem (where importance sampling works extremely well, as shown in our survey with Jean-Michel Marin), the stochastic volatility is more challenging and the fact that the Hamiltonian scheme applies to the missing data (volatility) as well as to the three parameters of the model is quite interesting. I however wonder at the appeal of this involved scheme when considering that the full conditional of the volatility can be simulated exactly

Posted in Statistics, University life with tags , , , , on August 25, 2010 by xi'an

There will be an RSS Read Paper session on October 13 given by Marc Girolami and B. Calderhead on Riemann manifold Langevin and Hamiltonian Monte Carlo methods that I definitely plan to attend. Here is the abstract:

The paper proposes Metropolis adjusted Langevin and Hamiltonian Monte Carlo sampling methods defined on the Riemann manifold to resolve the shortcomings of existing Monte Carlo algorithms when sampling from target densities that may be high dimensional and exhibit strong correlations. The methods provide fully automated adaptation mechanisms that circumvent the costly pilot runs that are required to tune proposal densities for Metropolis-Hastings or indeed Hamiltonian Monte Carlo and Metropolis adjusted Langevin algorithms. This allows for highly efficient sampling even in very high dimensions where different scalings may be required for the transient and stationary phases of the Markov chain. The methodology proposed exploits the Riemann geometry of the parameter space of statistical models and thus automatically adapts to the local structure when simulating paths across this manifold, providing highly efficient convergence and exploration of the target density. The performance of these Riemann manifold Monte Carlo methods is rigorously assessed by performing inference on logistic regression models, log-Gaussian Cox point processes, stochastic volatility models and Bayesian estimation of dynamic systems described by non-linear differential equations. Substantial improvements in the time-normalized effective sample size are reported when compared with alternative sampling approaches. MATLAB code that is available from the authors allows replication of all the results reported.

and as usual (400 word) comments can be submitted without any restriction.

## València 9 snapshot [3]

Posted in Statistics, University life with tags , , , , on June 7, 2010 by xi'an

Today was somehow a low-key day for me in terms of talks as I was preparing a climb in the Benidorm backcountry (thanks to the advice of Alicia Quiròs) and trying to copy routes from the (low oh so low!) debit wireless at the hotel. The session I attended in the morning was on Bayesian non-parametrics, with David Dunson giving a talk on non-parametric classification, a talk whose contents were so dense in information that it felt like three talks rather than one, especially when there was no paper to back it up! Katja Ickstadt modelled graphical dependence structures using non-parametrics but also mixtures of normals across different graph structures, an innovation I found interesting if difficult to interpret. Tom Loredo concluded the session with a broad and exciting picture of the statistical challenges found in spectral astronomy (even though I often struggle to make sense of the frequency data astronomers favour).

The evening talk by Ioanna Manolopoulou was a superbly rendered study on cell dynamics with incredible 3D animations of those cell systems, representing the Langevin diffusion on the force fields in those systems as evolving vector fields. And then I gave my poster on the Savage-Dickey paradox, hence missing all the other posters in this session… The main difficulty in presenting the result was not about the measure-theoretic difficulty, but rather in explaining the Savage-Dickey representation since this was unknown to most passerbys.


text:
# Enumerate non-isomorphic graphs on n vertices

In the following the graphs are assumed to be undirected and simple.

1.Enumerate the number of non-isomorphic graphs on $n$ vetrices where $n$ is fixed.

Here are some ideas I had:

The number of labeled graphs is $2^{\frac{n(n-1)}{2}}$.

So it is enough to find the number unlabeled graphs on $n$ vertices.I have no idea for this.

2.Enumerate the number of non-isomorphic graphs on $n$ vertices and $m$ edges where $n,m$ are fixed.

Can we find a closed formula for each of this?

Any help?

Thank you!

-
This is a rather difficult problem. See Sloane's oeis.org/A000088 which gives the number of graphs on $n$ vertices, and has many references. –  Grumpy Parsnip Jan 19 '12 at 20:22
"So it is enough to find the number unlabeled graphs on n vertices." The words non-isomorphic and unlabeled mean the same thing. –  Austin Mohr Jan 19 '12 at 21:34