arXiv subjects

Ethan Dlugie

Publications and source records attributed to Ethan Dlugie.

4 recordsLinked to original sources

arXiv2026

Braid groups and Burnside groups

There exists an exceptional quotient of braid groups $\text{Br}_4 \twoheadrightarrow \text{Br}_3$ that is related to many interesting constructions in algebra, topology, and geometry. This quotient map also descends to a quotient of "truncated" braid groups $\text{Br}_4(d) \twoheadrightarrow \text{Br}_3(d)$, which have an added torsion relation on their half twist generators. In this article, we find a presentation for the kernel of this truncated quotient map that takes the form of what we deem a "primitive" Burnside group. We give a few finiteness results on these primitive Burnside groups. Our methods are purely group theoretic, but we comment on an interpretation involving Lefschetz fibrations at the end.

math.GR↗

arXiv2025

The 3-strand braid group with torsion

In the 1950s, H. S. M. Coxeter considered the quotients of braid groups given by adding the relation that all half Dehn twist generators have some fixed, finite order. He found a remarkable formula for the order of these groups in terms of some related Platonic solids. Despite the inspiring apparent connection between these "truncated" braid groups and Platonic solids, Coxeter's proof boils down to a finite case check that reveals nothing about the structure present. We give a topological interpretation of the truncated 3-strand braid group that makes the connection with Platonic solids clear. One of our key tools is a formalism for orbifolds developed by A. Henriques that we think others would find interesting.

math.GT↗

arXiv2023

The Burau representation and shapes of polyhedra

We use a geometric approach to show that the reduced Burau representation specialized at roots of unity has another incarnation as the monodromy representation of a moduli space of Euclidean cone metrics on the sphere, as described by Thurston. Using the theory of orbifolds, we leverage this connection to identify the kernels of these specializations in some cases, partially addressing a conjecture of Squier. The 4-strand case is the last case where the faithfulness question for the Burau representation is unknown, a question that is related e.g. to the question of whether the Jones polynomial detects the unknot. Our results allow us to place the kernel of this representation in the intersection of several topologically natural subgroups of $B_4$.

math.GT↗

arXiv2017

On Uniform Large-Scale Volume Growth for the Carnot-Carathéodory Metric on Unbounded Model Hypersurfaces in $\mathbb{C}^2$

We consider the rate of volume growth of large Carnot-Carathéodory metric balls on a class of unbounded model hypersurfaces in $\mathbb{C}^2$. When the hypersurface has a uniform global structure, we show that a metric ball of radius $δ\gg 1$ either has volume on the order of $δ^3$ or $δ^4$. We also give necessary and sufficient conditions on the hypersurface to display either behavior.

math.DG↗