The Sigma Invariants of Thompson's Group F
نویسنده
چکیده
Thompson’s group F is the group of all increasing dyadic PL homeomorphisms of the closed unit interval. We compute Σm(F ) and Σm(F ;Z), the homotopical and homological Bieri-Neumann-Strebel-Renz invariants of F , and show that Σm(F ) = Σm(F ;Z). As an application, we show that, for every m, F has subgroups of type Fm−1 which are not of type FPm (thus certainly not of type Fm).
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