English

Exotic $\mathbb{R}^4$'s with Compactly Supported Diffeomorphisms

Geometric Topology 2025-08-05 v1

Abstract

We construct exotic copies of R4\mathbb{R}^4 with nontrivial compactly supported mapping class groups of arbitrarily large rank. This follows from a modification of the construction of the diffeomorphism corks of arXiv:2407.04696 that makes their exteriors simply-connected.

Keywords

Cite

@article{arxiv.2508.02017,
  title  = {Exotic $\mathbb{R}^4$'s with Compactly Supported Diffeomorphisms},
  author = {Abhishek Shivkumar},
  journal= {arXiv preprint arXiv:2508.02017},
  year   = {2025}
}
R2 v1 2026-07-01T04:32:20.940Z