English

Branched covers of twist-roll spun knots and turned twisted tori

Geometric Topology 2025-04-02 v3

Abstract

We prove that the double branched cover of a twist-roll spun knot in S4S^4 is smoothly preserved when four twists are added, and that the double branched cover of a twist-roll spun knot connected sum with a trivial projective plane is preserved after two twists are added. As a consequence, we conclude that the members of a family of homotopy CP2\mathbb{CP}^2s recently constructed by Miyazawa are each diffeomorphic to CP2\mathbb{CP}^2. We also apply our techniques to show that the double branched covers of odd-twisted turned tori are all diffeomorphic to S2×S2S^2 \times S^2, and show that a family of homotopy 4-spheres constructed by Juh\'asz and Powell are all diffeomorphic to S4S^4.

Keywords

Cite

@article{arxiv.2402.11706,
  title  = {Branched covers of twist-roll spun knots and turned twisted tori},
  author = {Mark Hughes and Seungwon Kim and Maggie Miller},
  journal= {arXiv preprint arXiv:2402.11706},
  year   = {2025}
}

Comments

New results have been added regarding the double branched covers of turned twisted tori, mainly centered around Theorems 1.9 to 1.11. This version is 15 pages with 7 figures. Comments welcome!