English

Equivalent non-isotopic spheres in 4-manifolds

Geometric Topology 2019-08-07 v3

Abstract

We construct infinitely many smooth oriented 4-manifolds containing pairs of homotopic, smoothly embedded 2-spheres that are not topologically isotopic, but that are equivalent by an ambient diffeomorphism inducing the identity on homology. These examples show that Gabai's recent "Generalized" 4D Lightbulb Theorem does not generalize to arbitrary 4-manifolds. In contrast, we also show that there are smoothly embedded 2-spheres that are both equivalent and topologically isotopic, but not smoothly isotopic.

Keywords

Cite

@article{arxiv.1806.07541,
  title  = {Equivalent non-isotopic spheres in 4-manifolds},
  author = {Hannah R. Schwartz},
  journal= {arXiv preprint arXiv:1806.07541},
  year   = {2019}
}

Comments

Final version, accepted for publication by the Journal of Topology

R2 v1 2026-06-23T02:35:30.145Z