Re: diagrams in computer algebra

[Michael J Healy <mjhealy@ece.unm.edu>]

Vasili,

Yes, I mean small.  All but FinSet (an appropriate version of it, anyway---certain functors into which are models, i.e.data respositories) are generated from finite graphs, through categorical completion elaborated with specified commutative diagrams, pullbacks, etc.

Regards,
Mike

On Oct 8, 2011, at 3:55 PM, Vasili I. Galchin wrote:

> Hi Mike,
> 
>     Do you really mean small category or do you mean finite category?
> If small category(potentially(<<< no pun intended) infinite), then I
> guess using Haskell is the right choice do to its lazy evaluation
> feature.
> 
> Regards,
> 
> Vasili
> 
> 
> On Mon, Oct 3, 2011 at 1:02 PM, Michael J Healy <mjhealy@ece.unm.edu> wrote:
>> Sergei,
>> 
>> My colleagues and I have been looking for something like this for a project.  We need to be able to specify small categories as the completions of finite graphs we are given, extend these by specifying commutative diagrams, pullbacks, etc, of interest, then define functors generated from graph homomorphisms, and take colimits of diagrams in Cat, etc etc.  We haven't found anything that does all this.  So, we're programming it in Haskell---one of our grad students knows the language.    We'll be happy to share our experience and will probably make the code available.  It's a work in progress.
>> 
>> Best regards,
>> Mike Healy
>> 

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