The genus two Goeritz group of $S^2 \times S^1$

Abstract

The genus-g Goeritz group is the group of isotopy classes of orientation-preserving homeomorphisms of a closed orientable 3-manifold that preserve a given genus-g Heegaard splitting of the manifold. In this work, we show that the genus-2 Goeritz group of $S^2 \times S^1$ is finitely presented, and give its explicit presentation.

minor changes; to appear in Mathematical Research Letters