A classification of centrally-symmetric and cyclic 12-vertex triangulations of $S^2 \times S^2$

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77800In this paper our main result states that there exist exactly three combinatorially distinct centrally-symmetric 12-vertex-triangulations of the product of two 2-spheres with a cyclic symmetry. We also compute the automorphism groups of the triangulations. These instances suggest that there is a triangulation of $S^2 \times S^2$ with 11 vertices -- the minimum number of vertices required.12 pages, 3 figuresCombinatorics57Q15; 52B70A classification of centrally-symmetric and cyclic 12-vertex triangulations of $S^2 \times S^2$text