Degree of maps on the sphere - MathOverflow [closed] most recent 30 from http://mathoverflow.net 2013-06-20T03:14:32Z http://mathoverflow.net/feeds/question/51035 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/51035/degree-of-maps-on-the-sphere Degree of maps on the sphere gilad 2011-01-03T16:51:08Z 2011-01-03T16:51:08Z <p>Given a map $f:B^n \to S^n$, where $B^n$ is the unit ball and $S^n$ is the unit sphere, is it true that the degree of <code>$f|_{S^n}$</code> is always 0, where <code>$f_{S^n}$</code> is the restriction of $f$ to $S^n$? If so, why?</p> <p>Thanks!</p>