Database of online seminar talks

Due to the current situation there are numerous online seminar talks organized all over the world. I was quite happy to discover this week that the website researchseminars.org maintains a useful database of online seminars and conferences, focusing on mathematics and related fields. The website is supported by the American Mathematical Society, the MIT and … Continue reading "Database of online seminar talks"

Triangulating real projective n-space

How many vertices do you need to triangulate the real projective n-space? From this blog post of Gil Kalai I learned about a recent preprint (arXiv:2009.02703) by Adiprasito-Avvakumov-Karasev where they construct triangulations with $\exp\big((1/2 + \mathcal{o}(1))\sqrt{n}\log{n}\big)\text{-many}$ vertices, which is the first construction needing subexponentially-many vertices. More information, also about the history of this problem, may … Continue reading "Triangulating real projective n-space"

Blockseminar on Dirac operators and scalar curvature

In mid-October we gathered for one week in Bollmannsruh (somewhat west of Berlin) to work our way through the seminal paper Positive scalar curvature and the Dirac operator on complete Riemannian manifolds by Gromov and Lawson. The hotel we stayed in lies directly at the beautiful lake Beetzsee. It was the perfect place to do … Continue reading "Blockseminar on Dirac operators and scalar curvature"

Seminar on soap bubbles and positive scalar curvature

Together with Rudolf Zeidler I am organizing a reading seminar this winter on generalized soap bubbles and positive scalar curvature. The goal of it is to read the corresponding preprint by Chodosh-Li (arXiv:2008.11888). The two main results we want to understand are the following: No closed aspherical manifold of dimension 4 or 5 admits a … Continue reading "Seminar on soap bubbles and positive scalar curvature"

Preise auf der DMV-Jahrestagung 2020

Die Jahrestagung 2020 der DMV fand vor zwei Wochen statt. Hier könnt ihr einen Kurzbericht dazu lesen: link. An dieser Stelle möchte ich kurz von den zwei auf dieser Jahrestagung verliehenen Preisen berichten: Anlässlich ihres 130-jährigen Bestehens hat die DMV die Minkowski-Medaille für besondere mathematische Forschungsleistungen geschaffen. Mit der Minkowski-Medaille will die DMV Mathematikerinnen und Mathematiker … Continue reading "Preise auf der DMV-Jahrestagung 2020"

Impressions from the SPP Conference

Some pictures from the SPP Conference in April 2019 in Münster. Let me start with a picture of the speaker of the SPP, Bernhard Hanke, explaining at the beginning of the conference the next steps leading to the second funding period of the SPP. (I unfortunately forgot to take a picture of Carsten Balleier from … Continue reading "Impressions from the SPP Conference"

AMS Special Session on the Mathematics of John Roe

There was a Special Session on Coarse Geometry, Index Theory, and Operator Algebras: Around the Mathematics of  John Roe at the Spring Central and Western Joint Sectional Meeting of the AMS last weekend to which Christopher and I were invited to give talks. John Roe passed away last year. His personal webpage is still online … Continue reading "AMS Special Session on the Mathematics of John Roe"

Bavarian Geometry/Topology Meeting

These days, there was the 2nd Bavarian Geometry/Topology Meeting, organized by Fabian Hebestreit and Markus Land, and hopefully becoming a tradition as the NRW topology meeting which by now had its 28th recurrent. Main event of the meeting were the lectures of Oscar Randal-Williams from Oxford, who discussed work on the cohomology of the mapping … Continue reading "Bavarian Geometry/Topology Meeting"