Abstract
We show that for any full and sufficiently transitive (i.e., flexible) group G of homeomorphisms of Cantor space, Aut(Aut(G)) = Aut(G). This class contains many generalisations of the Higman-Thompson g roups Gn,r, and the Rational group \({{\cal R}_2}\) of Grigorchuk, Nekrashevych, and Sushchanskiĭ. We also demonstrate that for generalisations Tn,r of R. Thompson’s group T, Aut(Aut(Tn,r)) = Aut(Tn,r). In the case of the groups Gn,r and Tn,r our results extend results of Brin and Guzmán for Thompson’s group T, and generalisations of Thompson’s group F.
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Olukoya, F. Automorphism towers of groups of homeomorphisms of Cantor space. Isr. J. Math. 244, 883–899 (2021). https://doi.org/10.1007/s11856-021-2196-z
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DOI: https://doi.org/10.1007/s11856-021-2196-z