Gpd

Authors: Emma Moore, Chris Wensley
Language: GAP 4
Operating System: Any
Current version: 1.03 (1931 KB)
README file: README (1 KB)
HTML: doc/chap0.html

Description

The Gpd package provides functions for computation with finite groupoids and their morphisms.

The first part is concerned with the standard constructions for connected groupoids, and for groupoids with more than one component. Groupoid morphisms are also implemented.

The second part implements graphs of groups and graphs of groupoids.
A graph of groups is a directed graph with a group at each vertex and with isomorphisms between subgroups on each arc.
This construction enables normal form computations for free products with amalgamation, and for HNN extensions, when the vertex groups come with their own rewriting systems.

For further information, see Emma Moore's Ph.D. thesis: moore.ps.gz

Next Version

Computationally, there are three types of connected groupoid:

those with identical object groups,
those with object groups conjugate in some supergroup,
those with object groups which are simply isomorphic.

GraphGpd attempted to implement the second case.
Gpd 1.01 restricted itself to the first case.
Gpd 1.04 will extend 1.03 to the second case.

Manual

Choose from the following formats:

pdf (238 KB),
online manual.

Authors

Emma Moore

email: emmajmoore@yahoo.co.uk

Chris Wensley
School of Computer Science
University of Wales
Bangor, Gwynedd
LL57 1UT, UK

email: c.d.wensley@bangor.ac.uk

GAP links:

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(gpd103.html, version 08/10/07)