English

Four manifolds with no smooth spines

Geometric Topology 2021-09-16 v3

Abstract

Let WW be a compact smooth 44-manifold that deformation retract to a PL embedded closed surface. One can arrange the embedding to have at most one non-locally-flat point, and near the point the topology of the embedding is encoded in the singularity knot KK. If KK is slice, then WW has a smooth spine, i.e., deformation retracts onto a smoothly embedded surface. Using the obstructions from the Heegaard Floer homology and the high-dimensional surgery theory, we show that WW has no smooth spines if KK is a knot with nonzero Arf invariant, a nontrivial L-space knot, the connected sum of nontrivial L-space knots, or an alternating knot of signature <4<-4. We also discuss examples where the interior of WW is negatively curved.

Keywords

Cite

@article{arxiv.2102.11416,
  title  = {Four manifolds with no smooth spines},
  author = {Igor Belegradek and Beibei Liu},
  journal= {arXiv preprint arXiv:2102.11416},
  year   = {2021}
}

Comments

12 pages, and this is the published version

R2 v1 2026-06-23T23:25:26.962Z