Exotic diffeomorphisms on a contractible 4-manifold surviving two stabilizations

Sungkyung Kang; JungHwan Park; Masaki Taniguchi

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arXiv · 2510.12394

Exotic diffeomorphisms on a contractible 4-manifold surviving two stabilizations

Sungkyung Kang·JungHwan Park·Masaki Taniguchi

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Abstract

We develop a $\mathrm{Pin}(2) \times \mathbb{Z}_2$-equivariant refinement of the lattice homotopy type for computing equivariant Seiberg--Witten Floer homotopy types. As an application, we construct a relatively exotic diffeomorphism on a compact contractible 4-manifold that survives two stabilizations.

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Sungkyung Kang, JungHwan Park, Masaki Taniguchi. 2025-10-14. Exotic diffeomorphisms on a contractible 4-manifold surviving two stabilizations. https://arxiv.org/abs/2510.12394

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