User juan ahtziri - MathOverflow most recent 30 from http://mathoverflow.net 2013-05-25T21:07:48Z http://mathoverflow.net/feeds/user/24695 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/100612/contractible-open-sets contractible open sets Juan Ahtziri 2012-06-25T17:53:44Z 2013-01-10T23:22:00Z <p>If $U\subset\mathbb{R}^n$ is an open and contractible subset such that there is a continuous function $f\colon U\to\mathbb{R}$ with only one minimum and the level curves of $f$ are connected by paths, then is $U$ homeomorphic to $\mathbb{R}^n$?</p>