Almost normal Heegaard surfaces
Abstract
Description
We present a new and shorter proof of Stocking's result that any strongly irreducible Heegaard surface of a closed orientable triangulated 3-manifold is isotopic to an almost normal surface. We also re-prove a result of Jaco and Rubinstein on normal spheres. Both proofs are based on the "reduction" technique introduced by the author.
13 pages, 2 figures. One figure added. The proof of a corollary was incorrect and had to be removed. The proof of the main result is essentially unchanged
13 pages, 2 figures. One figure added. The proof of a corollary was incorrect and had to be removed. The proof of the main result is essentially unchanged