This is the latest version, 2.43, of the GAP package IdRel.
This package is designed to compute a minimal set of generators for the module of the identities among relators of a group presentation. It does this using
• rewriting and logged rewriting: a self-contained implementation of the Knuth-Bendix process using the monoid presentation associated to the group presentation;
• monoid polynomials: an implementation of the monoid ring;
• module polynomials: an implementation of the right module over this monoid generated by the relators.
• Y-sequences: used as a rewriting way of representing elements of a free crossed module (products of conjugates of group relators and inverse relators).
The first version of IdRel was released in 1999 when Anne Heyworth was completing her Ph.D. It became an accepted GAP package in May 2015.
Bug reports, suggestions and comments are, of course, welcome. Please submit any issue at https://github.com/gap-packages/idrel/issues/ or email c.d.wensley@bangor.ac.uk.