English

Pair of pants decomposition of 4-manifolds

Geometric Topology 2018-03-16 v3

Abstract

Using tropical geometry, Mikhalkin has proved that every smooth complex hypersurface in CPn+1\mathbb{CP}^{n+1} decomposes into pairs of pants: a pair of pants is a real compact 2n2n-manifold with cornered boundary obtained by removing an open regular neighborhood of n+2n+2 generic hyperplanes from CPn\mathbb{CP}^n. As is well-known, every compact surface of genus g2g\geqslant 2 decomposes into pairs of pants, and it is now natural to investigate this construction in dimension 4. Which smooth closed 4-manifolds decompose into pairs of pants? We address this problem here and construct many examples: we prove in particular that every finitely presented group is the fundamental group of a 4-manifold that decomposes into pairs of pants.

Keywords

Cite

@article{arxiv.1503.05839,
  title  = {Pair of pants decomposition of 4-manifolds},
  author = {Marco Golla and Bruno Martelli},
  journal= {arXiv preprint arXiv:1503.05839},
  year   = {2018}
}

Comments

41 pages, 25 figures; exposition has been improved; the proof of Theorem 2 was incorrect, and it has been fixed. Accepted for publications in Algebr. Geom. Topol