With respect to the gruppenpest (and perhaps the actual situation concerning groupoids and categories), here is a quote from John Slater, who was the head of the MIT Physics departement and a leading American physicist: "It was at this point that Wigner, Hund, Heitler, and Weyl entered the picture with their "Gruppenpest": the pest of the group theory.... The authors of the "Gruppenpest" wrote papers which were incomprehensible to those like me who had not studied group theory, in which they applied these theoretical results to the study of the many electron problem. The practical consequences appreared to be negligible, but everyone felt that to be in the mainstream one had to learn about it. Yet there were no good texts from which one could learn group theory. It was a frustrating experience, worthy of the name of a pest. I had what I can only describe as a feeling of outrage at the turn which the subject had taken... As soon as this (Slater's) paper became known, it was obvious that a great many other physicists were as disgusted as I had been with the group-theoretical approach to the problem. As I heard later, there were remarks made such as "Slater has slain the '"Gruppenpest"'. I believe that no other piece of work I have done was so universally popular". I take this quote from Sternberg's book "Group Theory and Physics" who has taken it from Slater's autobiography. Maybe it has something to do with MIT ; -). Best, Jean-Pierre Marquis

Date: 15 mars 2006 21:08:42 GMT-05:00 To categories@mta.ca Subject: categories: Re: cracks and pots

For that remember (if any are as old as I) matrices good, groups bad

the gruppenpest

jim

Krzysztof Worytkiewicz wrote:

...

The blog in question is indeed more than dubious. Besides the "scientific" manicheism (group good, monoid bad...), what to think about ranking countries according to a "civilization index"? The blogger also claims he was mastering differential geometry and particle physics at age of 15, so he obviously was too busy and missed the provocative phase. Not a reason however to try to catch it up as an "adult".

Cheers

Krzysztof