On quasimorphisms invariant under automorphisms

Speaker(s)

Jarek Kędra

Affiliation

University of Aberdeen

Date

June 8, 2021, 4:30 p.m.

Information about the event

Zoom: 892 1108 9551 Password - type the number equal to rk(H^2((S^1)^{200};Z))

Seminar

Seminar Algebraic Topology

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Quasimorphisms comprise a good function theory on groups and many groups
admits an abundance of them. It was recently discovered by Brandenbursky and
Marcinkowski that the free group on two generators admits a quasimorphism
that is invariant under all automorphisms of F_2. I will present a more
recent construction, due to Bastien Karlhofer, of aut-invariant
quasimorphisms on various free products and graph products of groups.
Examples include groups like SL(2,Z), the braid group on three hair some
right angled Artin and Coxeter groups.

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