Subject: Computational Category Theory Tools

From: categories <[email-masked]>
Date: Sat, 16 Mar 1996 10:48:55 -0400 (AST)

Date: Sat, 16 Mar 1996 10:43:23 -0400 (AST)
From: Bob Rosebrugh <[email-masked]>

                         CATEGORIES DATABASE/TOOLS

A C program for storage of and computation with finitely presented
categories is now available as described below. 

The program is menu-based and stores finitely presented categories,
functors between them and finite-set valued functors from them.  The
storage format is the same as that used by the Carmody-Walters `kan'
program (available from the University of Sydney ftp site.)

Several tools for computation with finite categories are included. For
example, tests for equality of arrows, whether an object is initial and 
so on. A new implementation of the Todd-Coxeter procedure for computing 
left Kan extensions is complemented by an implementation of a procedure 
for computing right Kan extensions. Details are included in the user 
manual which may be found at 
ftp://sun1.mta.ca/pub/papers/rosebrugh/catuser.dvi

The program was written by Michael Fleming and Ryan Gunther while they 
were employed at Mount Allison University under NSERC Canada's USRA 
program. It is free software and without warranty. Indeed, it should be 
treated as an `alpha' version. Bug reports (to [email-masked]) 
are welcome, but may not be acted upon immediately.

The source code and compiled (Sun and DOS) versions are 
avalable for ftp from the directory
ftp://sun1.mta.ca/pub/sources/rosebrugh/{unix,DOS}
The compiled versions are named category.exe. A set of examples is 
found in the `examples' subdirectories. 

Bob Rosebrugh
<[email-masked]>