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The University of Southampton
Mathematical Sciences

Pure Maths Colloquium - QI rigidity of groups containing almost normal subgroups - Dr Alex Margolis (Technion) Seminar

15:00 - 16:00
15 February 2019
Building 54 (Mathematics), lecture room 10037 (10B), Highfield Campus, University of Southampton, SO17 1BJ

For more information regarding this seminar, please email Dr Jan Spakula at .

Event details

Abstract: A goal of geometric group theory is to understand to what extent the large scale geometry of a finitely generated group determines its algebraic structure. A subgroup H of G is said to be almost normal if every conjugate of H is commensurable to H. If G is finitely generated and H is almost normal, then G can be thought of as a coarse bundle over the coset space G/H. We show that quasi-isometries frequently preserve almost normal subgroups and the associated coarse bundle structure. A sample application is the following: any finitely presented group quasi-isometric to a Z-by-(∞ ended) group is also Z-by-(∞ ended). We make use of the notion of relative ends due to Kropholler and Roller. Our results build on work of Dunwoody and Mosher-Sageev-Whyte.

Speaker information

Dr Alex Margolis, Technion - Israel Institute of Technolog. Postdoc

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