Introduction

The &kan; package started out as part of Anne Heyworth's thesis }, and was designed to compute induced actions of categories (see also ).

This version of &kan; only provides functions for the computation of normal forms of representatives of double cosets of finitely presented groups, and is made available in support of the paper . Existing methods for computing double cosets in &GAP; are described in .

The package is loaded into &GAP; with the command gap> LoadPackage( "kan" );

This version of &kan; has been prepared for &GAP;~4.4.6. Some of the functions in the `automata` package are used to compute word acceptors and regular expressions for the languages they accept.

The `kbmag` package is also used to compute a word acceptor of a group G when G has no finite rewriting system. If `kbmag` is not available (the user is not on a UNIX system, or the C-programs have not been compiled), the file dckbmag.gi will not be read, so methods for the functions detailed in section 2.4.1 will not be available.

The information parameter InfoKan takes default value 0. When raised to a higher value, additional information is printed out.

Once the package is loaded, it is possible to check the installation is correct by running the test suite of the package with the following command. (The test file itself is tst/kan_manual.tst.) gap> ReadPackage( "kan", "tst/testall.g" ); + setting AssertionLevel to 0 to avoid recursion in Automata + Testing all example commands in the Kan manual + GAP4stones: 6 true (If `kbmag` is not loaded then a collection of error lines for Example 3 will be printed out.)

Please send bug reports, suggestions and other comments to the second author.

The &kan; package is subject to the &GAP; copyright regulations as detailed in the copyright notice in the &GAP; manual.