Radius of comparison and mean cohomological independence dimension

Ilan Hirshberg, N. Christopher Phillips

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We introduce a notion of mean cohomological independence dimension for actions of discrete amenable groups on compact metrizable spaces, as a variant of mean dimension, and use it to obtain lower bounds for the radius of comparison of the associated crossed product C-algebras. Our general theory, gives the following for the minimal subshifts constructed by Dou in 2017. For any countable amenable group G and any polyhedron Z, Dou's subshift T of ZG with density parameter ρ satisfies [Formula presented] If k=dim⁡(Z) is even and Hˇk(Z;Q)≠0, then [Formula presented] regardless of what ρ is.

Original languageEnglish
Article number108563
JournalAdvances in Mathematics
StatePublished - 17 Sep 2022


  • C-algebras
  • Mean dimension
  • Radius of comparison

ASJC Scopus subject areas

  • General Mathematics


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