Replacement of fixed sets for compact group actions: The 2ρ theorem

Sylvain Cappell, Shmuel Weinberger, Min Yan

Research output: Contribution to journalArticlepeer-review


We study the problem in transformation groups of realizing a manifold simple homotopy equivalent to a component of the fixed point set of a G-manifold as (a component of) the fixed set of another G-manifold equivariantly simple homotopy equivalent to the original one. We show that such replacability of (a component of) the fixed points is very often possible if the normal representation of the fixed point component is twice a complex representation (and a monodromy vanishes). In addition, we discuss for various compact groups some examples displaying topological phenomenona ranging from replacablility to rigidity.

Original languageEnglish (US)
Pages (from-to)53-77
Number of pages25
JournalPure and Applied Mathematics Quarterly
Issue number1
StatePublished - Jan 2012


  • Equivariant homotopy equivalence
  • Fixed point
  • Group action
  • Stratified space
  • Surgery theory

ASJC Scopus subject areas

  • General Mathematics


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