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Event

Catherine Pfaff (Queen's University) CANCELED

Wednesday, November 15, 2023 15:00to16:00
Burnside Hall Room 920, 805 rue Sherbrooke Ouest, Montreal, QC, H3A 0B9, CA

TITLE / TITRE
Graphs, R-trees, & what happens when you iterate a free group automorphism.

ABSTRACT / RÉSUMÉ

One of the most beautiful interplays in mathematics is between a deformation space and its symmetry group. Let X be a combinatorial object (such as a graph) or a topological object (such as a surface). Suppose X admits some further structure (such as a metric) in a nonunique way. Then the possible choices for the further structure are organized into a deformation space, on which a suitable group of symmetries of X acts. For a surface, this is the mapping class group acting on Teichmuller space, and for a graph, this is the free group outer automorphism group acting on Culler-Vogtmann Outer Space. We discuss 2 different notions of "typical R-trees" arising from automorphisms of a free group and their action on Culler-Vogtmann Outer Space. Results presented are joint work with I. Kapovich, J. Maher, and S.J. Taylor.

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