A new approach to proving hyperbolicity

Version 0.999
Released 2019-12-19

This project is maintained by Markus Pfeiffer

Build Status Code Coverage Binder

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 4.10.1 or later, and does not require compilation of a kernel module.

It depends on the GAP packages GAPDoc, io, digraphs, kbmag, and datastructures.


Full information and documentation can be found in the manual, also available as PDF doc/manual.pdf or as HTML doc/chap0.html, in the distributed package tarball.

For further information also check the package homepage at


Bug reports and feature requests

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



JupyterKernel is free software; you can redistribute it and/or modify it under the terms of the BSD 3-clause license.

For details see the files COPYRIGHT.md 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.