I am unsure which is the right spelling (if there even is a ‘right’ spelling), but maybe native speakers can enlighten me: When should I use


* *fixed point*
* *fixed-point*
* *fixedpoint*


when I refer to the point itself, but also in composite works (“fixed point equation”, “fixed-point juggling”, “fixed-point operator”)?


And do the same rules apply to *prefixed points*?



fixedpoint or fixed point or fixed-point
When it is a phrasal adjective you use a hyphen. 


So when it modifies a noun uses a hyphen: fixed−point equation, fixed−point operator, fixed-point theory.


But, on the other hand, take a fixed point of the operator, consider the fixed point in X. We have found our fixed point. 


When the phrasal adjective ends with -ly, drop the hyphen, the -ly is your separator. So perfectly separated set


... Fixedpoint is ugly (never use it).


