<lift:loc locid="stock.discuss"></lift:loc>
Width and finite extinction time of Ricci flow
This is an expository article with complete proofs intended for a general non-specialist audience. The results are two-fold. First, we discuss a geometric invariant, that we call the width, of a manifold and show how it can be realized as the sum of areas of minimal 2-spheres. For instance, when $M$ is a homotopy 3-sphere, the width is loosely speaking the area of the smallest 2-sphere needed to ``pull over'' $M$. Second, we use this to conclude that Hamilton's Ricci flow becomes extinct in finite time on any homotopy 3-sphere. We have chosen to write this since the results and ideas given here are quite useful and seem to be of interest to a wide audience.
  • Pls. be polite and constructive.
  • You can input La|TeX for math formulas. E.g. $$x = {-b \pm \sqrt{b^2-4ac} \over 2a}$$
  • Any attachment files should still be uploaded to arXiv.org