Is there a reference of a proof of the following statement?
If $U$ is a nonempty convex open subset of $\Bbb R^n$, then $U$ is diffeomorphic to $\Bbb R^n$.
Asked
Active
Viewed 94 times
3
user302934
- 1,698
-
2The answer is positive even for a star shape. See MO article. – mathcounterexamples.net Sep 02 '20 at 13:42
-
It was asked in MSE at least three times before, and answered as well. – Moishe Kohan Sep 02 '20 at 21:03
-
Also https://math.stackexchange.com/questions/1869739/why-are-geodesically-convex-sets-diffeomorphic-to-bbb-rn/1869934, I am sure, there are more. – Moishe Kohan Sep 02 '20 at 22:40