Geometric Group Theory Seminar - Katherine Goldman

Ohio State Garden of Constants
March 20, 2025
1:50 pm - 2:50 pm
SM1138

Date Range
2025-03-20 13:50:00 2025-03-20 14:50:00 Geometric Group Theory Seminar - Katherine Goldman Katherine GoldmanMcGill UniversityTitleResidual properties of 2-dimensional Artin groupsAbstractIt is a longstanding open question to determine which Artin groups are residually finite. Past results have followed from linearity (e.g., for spherical-type) or product decompositions in rank 3. We present a new approach to this problem using intermediate quotients to so-called Shephard groups. These Shephard groups possess their own interesting (and sometimes counterintuitive) geometry which we can leverage to give new information about their corresponding Artin groups in some cases. As a highlight of this connection, we show that an Artin group which is simultaneously 2-dimensional, hyperbolic-type, and FC-type is residually finite. One of the key features of the proof we will discuss is the fact that hyperbolic-type 2-dimensional Shephard groups are relatively hyperbolic, which is almost never true of Artin groups. SM1138 America/New_York public

Katherine Goldman
McGill University

Title
Residual properties of 2-dimensional Artin groups

Abstract
It is a longstanding open question to determine which Artin groups are residually finite. Past results have followed from linearity (e.g., for spherical-type) or product decompositions in rank 3. We present a new approach to this problem using intermediate quotients to so-called Shephard groups. These Shephard groups possess their own interesting (and sometimes counterintuitive) geometry which we can leverage to give new information about their corresponding Artin groups in some cases. As a highlight of this connection, we show that an Artin group which is simultaneously 2-dimensional, hyperbolic-type, and FC-type is residually finite. One of the key features of the proof we will discuss is the fact that hyperbolic-type 2-dimensional Shephard groups are relatively hyperbolic, which is almost never true of Artin groups.

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