2022/03/18 by Venturello, Lorenzo
#Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2203.10003
In this note we construct a flag simplicial 3-sphere Δ with the following properties: - Δ is not a suspension; - Δ has no edge that can be contracted to obtain another flag sphere; - The only equators (induced subcomplexes which are spheres of codimension 1) of Δ are vertex links. Our construction has 12 vertices, the minimum number of vertices such a simplicial complex can have. This answers a question posed by Chudnovsky and Nevo.