# Seifert–Weber space

The Seifert–Weber space is a rational homology sphere, and its first homology group is isomorphic to $\mathbb Z_5^3$. William Thurston conjectured that the Seifert–Weber space is not a Haken manifold, that is, it does not contain any incompressible surfaces; Burton, Rubinstein & Tillmann (2012) proved the conjecture with the aid of their computer software Regina.