Sunday, January 17, 2010

Category Theory 2010, Genoa, 20 - 26 June 2010

The web site of CT2010 is now available.

The invited speakers are:
Olivia Caramello, Cambridge-Pisa,
Denis-Charles Cisinski, Paris,
George Janelidze, Cape Town,
André Joyal, Montreal,
Matias Menni, La Plata,
Mark Weber, Paris.


John Baez is changing course

John Baez has announced that he is going to Singapore for a year, and at the same time is changing his research direction. He would like to try his hand "at some slightly more ‘practical’ endeavors", and has a "growing urge to help save the planet".

He is going to the Centre for Quantum Technologies, a research institute whose mission is to conduct interdisciplinary theoretical and experimental research into the fundamental limits to information processing, and is directed by Artur Ekert, who is a professor of quantum physics at the Mathematical Institute, Oxford University. (Bob Coecke, who uses category theory to study quantum information is also at Oxford but at the Computing laboratory.)

There John is likely to meet one of our Como physicists, Giulio Casati, actually the founder of the Como Science Faculty, winner of the Enrico Fermi prize (2008), Somaini prize (1991), and associate editor of Chaos, Solitons & Fractals. John may have more success than I in interesting Giulio in category theory.

The work John is developing on n-category cafe in a sequence of posts regards graphical reasoning in biological and physical systems. He might be interested in a paper of mine with Katis and Sabadini, "On the algebra of feedback and systems with boundary" (Rendiconti del Circolo Matematico di Palermo Serie II, Suppl. 63 (2000), 123-156), in which section 4.2 is called "Towards an algebraic foundation for electrical circuit theory". A version of the paper is available called here. Another paper which might be of interest is called "Systems with discrete geometry" and is available here.

Given his desire to save the world I have the sneaking suspicion that one day John will end up in politics like another young mathematician with name B***, who also wrote an article seeking to popularize category theory. (I regret to say that I found the article of B*** particularly unconvincing).


Thursday, January 07, 2010

Medici Money

One of my humanist friends, L., worries about the growing power of computer "technicians" in society. The public services in Italy are rapidly being computerized, and access to them requires following the plans and fantasies of the technicians.
However he has a sneaking admiration for mathematicians - they are more philosophers than scientists or technologists.

I tried to point out to him that numbers, since Pacioli (Summa de arithmetica, geometria, proportioni et proportionalita,Venice 1494) (and long before), have ruled us much more tightly.

When I came to Italy, trying to manage my own numbers, I wrote (with Katis and Sabadini) a categorical analysis of partita doppia (double-entry bookkeeping) (which had always puzzled me since a child). It involved the compact closed structure on Span(Graph), and in fact lead to another very abstract paper (P. Katis, R.F.C. Walters, The compact closed bicategory of left adjoints, Math. Proc. Camb. Phil. Soc., 130, 77-87, 2001).

These thoughts came back to me recently when I tried to read a book by Tim Parks (Medici Money, Profile Books, 2005). I say 'tried to' because I found the book quite indigestible despite my interest in the subject matter. It is a book without concentrated form or idea. I am surprised because I found Tim Parks' book, Italian Neighbours, on a foreigner coming to live and work in Italy well-organized and very pleasant. That book I feel I should have read before moving to Italy myself - almost every experience in it I have lived myself.

For a book on money I much prefer Frozen Desire, by James Buchan (Picador 1997), a book I return to, even if money remains to me still a mystery.

Perhaps if I read more carefully Sean Carmody's recent posts on Stubborn Mule I might be further enlightened. Or perhaps he should use some of the category theory he knows to formalize and make more precise his annecdotal explanations.

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