Computational Methods for Finitely Generated Monoids and Groups
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Polynomial-time proofs that groups are hyperbolic.ipynb

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walrus - Computational Methods for Finitely Generated Monoids and Groups

The main feature of this package currently is an implementation of methods for proving hyperbolicity of finitely presented groups in polynomial time based on an algorithm described in the paper "Polynomial-time proofs that groups are hyperbolic".

For lightweight experimentation with walrus you can use the MyBinder demo in your browser.

Future work on this package will include a more sophisticated implementation of the RSym procedure, integration of Knuth-Bendix methods from kbmag for hyperbolicity testing, and the word-problem solver as described in "Polynomial-time proofs that groups are hyperbolic".


This package works with GAP version 4.9.1 or later, and does not require compilation of a kernel module.

Along with packages that are distributed with GAP (GAPDoc, io, digraphs, and kbmag), it depends on the as-yet not deposited package datastructures, which needs to be installed and compiled manually.


Full information and documentation can be found in the manual, available as PDF doc/manual.pdf or as HTML htm/chapters.htm, or on the package homepage at

Bug reports and feature requests

Please submit bug reports and feature requests via our GitHub issue tracker:


walrus is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

For details see the files and LICENSE.

Why walrus?

The Walrus is Captain Flint's ship in Robert Louis Stevenson's Treasure Island. Sailing ships come with a lot of ropes, which, when you think about it, are glorified strings.