2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68095An updated proof of a 1933 theorem of Goeritz, exhibiting a finite set of generators for the group of automorphisms of the 3-sphere that preserve a genus two Heegaard splitting. The group is analyzed via its action on a certain connected 2-complex. (The analogous problem for higher genus Heegaard splittings appears to remain unresolved.)13 pages, 10 figuresGeometric Topology57N12text