Morse theory for manifolds with boundary
arXiv:1207.3066 · doi:10.2140/agt.2016.16.971
Abstract
We develop Morse theory for manifolds with boundary. Besides standard and expected facts like the handle cancellation theorem and the Morse lemma for manifolds with boundary, we prove that, under a topological assumption, a critical point in the interior of a Morse function can be moved to the boundary, where it splits into a pair of boundary critical points. As an application, we prove that every cobordism of manifolds with boundary splits as a union of left product cobordisms and right product cobordisms.
v4. 38 pages, 20 figures, minor revision, updated references to Braess, Jankowski--Rubinstein and Hajduk