University of Illinois Urbana-Champaign

Certain free group functions and untangling closed curves on surfaces

Gupta, Neha

Content Files
GUPTA-DISSERTATION-2016.pdf

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https://hdl.handle.net/2142/92691

Description

Title
Certain free group functions and untangling closed curves on surfaces
Author(s)
Gupta, Neha
Issue Date
2016-05-03
Director of Research (if dissertation) or Advisor (if thesis)
Kapovich, Ilya
Doctoral Committee Chair(s)
Schupp, Paul
Committee Member(s)
  • Leininger, Chris
  • Mineyev, Igor
Department of Study
Mathematics
Discipline
Mathematics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Date of Ingest
2016-11-10T17:49:21Z
Keyword(s)
  • Untangling curves
  • free groups
Abstract
This thesis primarily addresses the problem of untangling closed geodesics in finite covers of hyperbolic surfaces. Our motivation comes from results of Scott and Patel. Scott's result tells us that one can always untangle a closed geodesic on a hyperbolic surface in a finite degree cover. Our goal is to quantify the degree of this cover in which the geodesic untangles in terms of the length of the geodesic. Our approach is to introduce and study the notions of primitivity, simplicity and non-filling index functions for finitely generated free groups. In joint work with Ilya Kapovich we obtain lower bounds for these functions and relate these free group results back to the setting of hyperbolic surfaces. Chapters 1-6 in parts comprise of a joint paper with Kapovich that is under review. Chapter 7 discusses the problem of Nielsen equivalence in a particular class of generic groups.
Graduation Semester
2016-08
Type of Resource
text
Permalink
http://hdl.handle.net/2142/92691
Copyright and License Information
Copyright 2016 Neha Gupta

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