English

The topological and smooth Hausmann-Weinberger invariants disagree

Geometric Topology 2026-01-29 v2

Abstract

For π\pi a finitely presented group, Hausmann and Weinberger defined q(π)Zq(\pi) \in \mathbb Z to be the minimum Euler characteristic over all closed, oriented 44-manifolds with fundamental group π\pi. This short note establishes that this minimum value in general differs depending on whether one minimizes over topological manifolds or only those admitting a smooth structure.

Keywords

Cite

@article{arxiv.2601.07040,
  title  = {The topological and smooth Hausmann-Weinberger invariants disagree},
  author = {Mike Miller Eismeier},
  journal= {arXiv preprint arXiv:2601.07040},
  year   = {2026}
}

Comments

3 pages. Comments welcome