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9 - On proofs in finitely presented groups

Published online by Cambridge University Press:  20 April 2010

George Havas
Affiliation:
ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland
Colin Ramsay
Affiliation:
ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland
C. M. Campbell
Affiliation:
University of St Andrews, Scotland
M. R. Quick
Affiliation:
University of St Andrews, Scotland
E. F. Robertson
Affiliation:
University of St Andrews, Scotland
G. C. Smith
Affiliation:
University of Bath
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Summary

Abstract

Given a finite presentation of a group G, proving properties of G can be difficult. Indeed, many questions about finitely presented groups are unsolvable in general. Algorithms exist for answering some questions while for other questions algorithms exist for verifying the truth of positive answers. An important tool in this regard is the Todd–Coxeter coset enumeration procedure. It is possible to extract formal proofs from the internal working of coset enumerations. We give examples of how this works, and show how the proofs produced can be mechanically verified and how they can be converted to alternative forms. We discuss these automatically produced proofs in terms of their size and the insights they offer. We compare them to hand proofs and to the simplest possible proofs. We point out that this technique has been used to help solve a longstanding conjecture about an infinite class of finitely presented groups.

Keywords: finitely presented group, proof, Todd–Coxeter coset enumeration, Hilbert's 24th problem, Fibonacci group, van Kampen diagram, trivial group, Andrews–Curtis conjecture.

Introduction

Many theorems in group theory are based on the results of computations. Indeed, often, the computations are now done on machines. Comprehensive details about computing with finitely presented groups appear in. Of particular relevance to our considerations are the chapters on coset enumeration and also a brief review of computability issues.

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Publisher: Cambridge University Press
Print publication year: 2007

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  • On proofs in finitely presented groups
    • By George Havas, ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland, Colin Ramsay, ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland
  • Edited by C. M. Campbell, University of St Andrews, Scotland, M. R. Quick, University of St Andrews, Scotland, E. F. Robertson, University of St Andrews, Scotland, G. C. Smith, University of Bath
  • Book: Groups St Andrews 2005
  • Online publication: 20 April 2010
  • Chapter DOI: https://doi.org/10.1017/CBO9780511721205.010
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  • On proofs in finitely presented groups
    • By George Havas, ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland, Colin Ramsay, ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland
  • Edited by C. M. Campbell, University of St Andrews, Scotland, M. R. Quick, University of St Andrews, Scotland, E. F. Robertson, University of St Andrews, Scotland, G. C. Smith, University of Bath
  • Book: Groups St Andrews 2005
  • Online publication: 20 April 2010
  • Chapter DOI: https://doi.org/10.1017/CBO9780511721205.010
Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

  • On proofs in finitely presented groups
    • By George Havas, ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland, Colin Ramsay, ARC Centre for Complex Systems, School of Information Technology and Electrical Engineering, The University of Queensland
  • Edited by C. M. Campbell, University of St Andrews, Scotland, M. R. Quick, University of St Andrews, Scotland, E. F. Robertson, University of St Andrews, Scotland, G. C. Smith, University of Bath
  • Book: Groups St Andrews 2005
  • Online publication: 20 April 2010
  • Chapter DOI: https://doi.org/10.1017/CBO9780511721205.010
Available formats
×