Tue, 17 Nov 2026
15:00
L6

TBC

Giorgio Mangioni
(Heriot-Watt University, Edinburgh)
Tue, 20 Oct 2026
15:00
L6

The conjugacy problem in twisted right-angled Artin groups

Gemma Crowe
Abstract
There exists a vast literature around the idea of constructing groups (and monoids) via some correspondence with finite simple graphs. One well-known example is right-angled Artin groups (RAAGs), where edges in our graph correspond to commuting generators in our group.
 
In this talk, we will discuss an adaptation of this group, known as twisted RAAGs (T-RAAGs), where we introduce the option of ‘Klein-bottle’ relations, to correspond to directed edges of our graph. We will then survey some results about these groups (including many open questions!) and show T-RAAGs have a decidable conjugacy problem. This is based on joint work with Islam Foniqi.
Tue, 13 Oct 2026
15:00
L6

Learning Group Geometry: Graph Embeddings for the Word Problem, Cryptanalysis, and Group Invariants

Elisabeth Fink
Abstract

This talk presents a geometric machine learning framework for resolving algebraic decision problems, with a focus on the Word Problem and post-quantum cryptography. Unreduced words in the Baumslag-Solitar group BS(1,2) and Artin groups are mapped into graphs constructed by their specific generators and defining relations.

To construct a continuous representation of the underlying group, a Graph Neural Network is trained using contrastive triplets (W,P,N). In this setup, W represents a base word, P is a positive example (a word algebraically equivalent to W), and N acts as a negative decoy (a non-equivalent word). The network embeds these graphs into a 128-dimensional unit sphere, forcing algebraically identical elements to cluster together while separating distinct elements.

This learned geometric space offers direct computational solutions to classical group-theoretic problems. It is used to successfully launch a cryptanalytic attack on the Wagner-Magyarik cryptosystem. Furthermore, by directly linking the continuous embedding back to the discrete metric space of the group, a variant network architecture accurately predicts the reduced geodesic length of randomly generated sequences.

The framework is subsequently applied to Right-Angled Artin Groups (RAAGs) and random Artin groups to evaluate the Nielsen equivalence of subgroup generating sets. The presentation concludes by outlining how these structural graph representations can be adapted to estimate Gromov hyperbolicity and extract other coarse geometric invariants from infinite groups.
 

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