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Physical Sciences and Mathematics Commons

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Mathematics

City University of New York (CUNY)

Theses/Dissertations

Geometric Group Theory

Publication Year

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

A Stronger Strong Schottky Lemma For Euclidean Buildings, Michael E. Ferguson Feb 2023

A Stronger Strong Schottky Lemma For Euclidean Buildings, Michael E. Ferguson

Dissertations, Theses, and Capstone Projects

We provide a criterion for two hyperbolic isometries of a Euclidean building to generate a free group of rank two. In particular, we extend the application of a Strong Schottky Lemma to buildings given by Alperin, Farb and Noskov. We then use this extension to obtain an infinite family of matrices that generate a free group of rank two. In doing so, we also introduce an algorithm that terminates in finite time if the lemma is applicable for pairs of certain kinds of matrices acting on the Euclidean building for the special linear group over certain discretely valued fields.


Stable Commutator Length In Amalgamated Free Products, Timothy Susse Jun 2014

Stable Commutator Length In Amalgamated Free Products, Timothy Susse

Dissertations, Theses, and Capstone Projects

We show that stable commutator length is rational on free products of free Abelian groups amalgamated over Zk, a class of groups containing the fundamental groups of all torus knot complements. We consider a geometric model for these groups and parameterize all surfaces with specified boundary mapping to this space. Using this work we provide a topological algorithm to compute stable commutator length in these groups. We then use the combinatorics of this algorithm to prove that for a word w in the (p, q)-torus knot complement, scl(w) is quasirational in p and q. Finally, we analyze central …