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Random walks and boundaries of CAT(0) cubical complexes. (English) Zbl 1494.20059

Summary: We show under weak hypotheses that the pushforward \(\{Z_no\}\) of a random-walk to a CAT(0) cube complex converges to a point on the boundary. We introduce the notion of squeezing points, which allows us to consider the convergence in either the Roller boundary or the visual boundary, with the appropriate hypotheses. This study allows us to show that any nonelementary action necessarily contains regular elements, that is, elements that act as rank-1 hyperbolic isometries in each irreducible factor of the essential core.

MSC:

20F65 Geometric group theory
20F67 Hyperbolic groups and nonpositively curved groups
20P05 Probabilistic methods in group theory
60J50 Boundary theory for Markov processes