# Kirby

## Which compact boundaryless 3-manifolds embed smoothly in the 4-sphere? โ โ โ

Author(s): Kirby

**Problem**Determine a computable set of invariants that allow one to determine, given a compact boundaryless 3-manifold, whether or not it embeds smoothly in the 4-sphere. This should include a constructive procedure to find an embedding if the manifold is embeddable.

Keywords: 3-manifold; 4-sphere; embedding