English

The Hopf invariant and simplex straightening

Differential Geometry 2009-03-16 v2

Abstract

Let M be a closed 3-manifold which can be triangulated with N simplices. We prove that any map from M to a genus 2 surface has Hopf invariant at most C^N. Let X be a closed oriented hyperbolic 3-manifold with injectivity radius less than epsilon at one point. If there is a degree non-zero map from M to X, then we prove that epsilon is at least C^{-N}.

Keywords

Cite

@article{arxiv.0709.1247,
  title  = {The Hopf invariant and simplex straightening},
  author = {Larry Guth},
  journal= {arXiv preprint arXiv:0709.1247},
  year   = {2009}
}

Comments

17 pages. In the first version of the paper, there was a mistake on page 6 in the proof of Lemma 1. The paper is corrected, and some parts have been simplified

R2 v1 2026-06-21T09:15:22.241Z