- At 21.25 23/12/99 -0800, you wrote:
>From: "William H. Rowan" <rowan@...>

theory.

>

>Hello all,

>

>I heard once about some category-theoretic generalization of commutator

>The idea was to define the commutator just using joins and meets in the

lattice

>of congruences of pullbacks of the algebra, or something like that. It was

The only person I know who has worked in commutators and category theory

>general enough that it made sense in categories other than categories of

>algebras. Has anyone heard anything about this?

>

>Bill Rowan

>

is Maria Cristina Pedicchio, an italian lady working at the University

of Trieste. Here is her email:

pedicchi@...

She has also a webpage but it does not look updated.

http://mathsun1.univ.trieste.it/people/pedicchio_eng.html

She's a nice person and if you write her she'll answer.

Ciao, Paolo >

I swore I had the paper, but when I looked for it I only found

> I heard once about some category-theoretic generalization of commutator theory.

> The idea was to define the commutator just using joins and meets in the lattice

> of congruences of pullbacks of the algebra, or something like that. It was

> general enough that it made sense in categories other than categories of

> algebras. Has anyone heard anything about this?

>

this one:

Some characterizations of the commutator, A. Day and H.P. Gumm,

Algebra Universalis 29 (1992), 61-78

It might be a place to start, though.

---David Hobby- You might want to check the following URL:

http://www.cs.elte.hu/~ewkiss/publist.html

there are several papers there that might be close to what you are looking

for.

----- Original Message -----

From: David Hobby <hobby@...>

To: <univalg@onelist.com>

Sent: Thursday, January 06, 2000 8:11 AM

Subject: Re: [univalg] Commutator theory

> >

> > I heard once about some category-theoretic generalization of commutator

theory.

> > The idea was to define the commutator just using joins and meets in the

lattice

> > of congruences of pullbacks of the algebra, or something like that. It

was

> > general enough that it made sense in categories other than categories of

> > algebras. Has anyone heard anything about this?

> >

> I swore I had the paper, but when I looked for it I only found

> this one:

>

> Some characterizations of the commutator, A. Day and H.P. Gumm,

> Algebra Universalis 29 (1992), 61-78

>

> It might be a place to start, though.

>

> ---David Hobby

>

>

>