Equality cases of the Alexandrov–Fenchel inequality are not in the polynomial hierarchy

Autor: Swee Hong Chan, Igor Pak
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Forum of Mathematics, Pi, Vol 12 (2024)
Druh dokumentu: article
ISSN: 2050-5086
DOI: 10.1017/fmp.2024.20
Popis: Describing the equality conditions of the Alexandrov–Fenchel inequality [Ale37] has been a major open problem for decades. We prove that in the case of convex polytopes, this description is not in the polynomial hierarchy unless the polynomial hierarchy collapses to a finite level. This is the first hardness result for the problem and is a complexity counterpart of the recent result by Shenfeld and van Handel [SvH23], which gave a geometric characterization of the equality conditions. The proof involves Stanley’s [Sta81] order polytopes and employs poset theoretic technology.
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