Some applications of commutators

Ville Salo
University of Turku, Finland

Date(s) : 07/11/2017   iCal
11 h 00 min - 12 h 00 min

To a group action and a sigma-algebra of clopen sets on some space, we associate a “controlled group action”, where the action of the group can depend on events in the sigma-algebra. We discuss the basic properties of this definition, and then give some applications when the controlled group is perfect, arising from a simple commutator trick. Applications are given in two contexts related to logical gates, and in two contexts related to groups of symbolic-dynamical origin. We also get a short proof of the classical fact that there are uncountably many non-isomorphic finitely generated groups.


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