# Mazur manifold

> 4-dimensional contractible smooth manifold with boundary that is not diffeomorphic to the 4-ball

**Wikidata**: [Q6799047](https://www.wikidata.org/wiki/Q6799047)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Mazur_manifold)  
**Source**: https://4ort.xyz/entity/mazur-manifold