Syzygies of string modules for special biserial algebras
: discrete models and the SBStrips package for GAP

  • Joseph Allen

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)


We present discrete models of special biserial (SB) algebras and their string modules, drawing inspiration from cellular automata, and cast new light on patterns among syzygies. We explore applications of our models to open questions in homological algebra regarding certain triangulated subcategories of derived categories, with implications for the finitistic dimension conjectures.

More pertinently, our models provide the inner workings for a new, original GAP package called SBStrips, written and implemented by the author. Its source code is freely available online and its documentation is included as an appendix. The package calculates syzygies of string modules (and much more besides) using specialised methods much more efficient than the general methods currently employed by the QPA package.
Date of Award28 Sept 2021
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorJeremy C Rickard (Supervisor) & Peter J Green (Supervisor)


  • algebra
  • special biserial algebra
  • syzygy
  • representation theory
  • homological algebra
  • finitistic dimension
  • derived category
  • string module
  • band module
  • string
  • band

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