2026/07/30 by Yuezhao Li, Guo Chuan Thiang
Physics and Astronomy · Mathematics · #math-ph #cond-mat.mes-hall #math.KT #math.MG #math.MP #math.OA #msc:81R40 #msc:81R15 #msc:81V70 #msc:19K56 #msc:46L80
arxiv created 2026/07/30 · arxiv updated 2026/07/31
Operators invariant under a symmetry group are also invariant under any finite-index subgroup. The equivariant indices of such operators must be consistent under symmetry breaking. We use this principle to establish a canonical weak/strong dichotomy for equivariant indices, building on an idea originating in the theory of topological insulators in solid-state physics. We also study the relationship to coarse-geometric, or macroscopic, indices.