Exotic families of embeddings
Dave Auckly, Daniel Ruberman
TL;DR
The paper develops a framework to produce exotic embeddings of 3‑manifolds in 4‑manifolds that are topologically trivial but smoothly nontrivial, and it proves two main results: infinite non‑isotopic embeddings of certain homology 3‑spheres into $S^4$ with diffeomorphic complements, and infinite higher‑dimensional families of embeddings parameterized by spheres. The authors build these phenomena via cork twists (notably infinite order corks) and a stabilization technique that couples submanifold sums with families of diffeomorphisms, then detect nontriviality using gauge‑theoretic invariants (Donaldson and Konno’s Seiberg‑Witten‑based family invariants). They provide explicit constructions based on $E(2)$ and log transforms, and extend the analysis to families of submanifolds, introducing a marking framework and multiset invariants to distinguish different parameterizations. The work suggests a parameterized cork‑theoretic mechanism for embedding phenomena and broadens the scope of exotic smooth structures in dimension four with concrete, computable invariants and examples.
Abstract
We construct a number of topologically trivial but smoothly non-trivial families of embeddings of 3-manifolds in 4-manifolds. These include embeddings of homology spheres in $S^4$ that are not isotopic but have diffeomorphic complements, and families (parameterized by high-dimensional spheres) of embeddings of any 3-manifold that embeds in a blown-up K3 surface. In each case, the families are constructed so as to be topologically trivial in an appropriate sense. We also illustrate a general technique for converting a non-trivial family of embeddings into a non-trivial family of submanifolds.
