As evident from the subject, this personal answer to Toby Bartels is intended to have general incumbency. Dear Toby, thanks for this msage, i will try to explain: Toby Bartels wrote:
Eduardo J. Dubuc wrote at first:
Dear Toby, your choice of example is very unfortunate. Mac Lane wrote that category theory was invented to define functor, and that functor was invented to define "natural" transformation.
Yes, I know; that was quite deliberate.
Well, I said "unfortunate" for those that are in favor of introducing the name "evil" (or any other name) as a definition of "not invariant under equivalence". You see, this is because to introduce a name the property has to be important enough and of frequent use. To sustain your case you should have given examples of properties (or concepts) which not being very important and of frequent use, have nevertheless an universally accepted proper name.
but beyond that I have no idea what upsets you, and I'm not going to worry about it any more.
I appreciate that you had worried at some point, and I am glad you do not worry any more. I try to explain why I sounded upset with you in my last mail because it has a general interest concerning the question of whether we are a subculture or part of the mainstream of mathematics. Recall that this was my only mail that concerns you in particular, and that it was in response to a mail of you, and that it was that mail that I felt upsetting. I quote from it:
Shall we stop saying "natural" and say "invariant under composition"? Or is that term allowed under the grandfather clause,
"the grandfather clause" is not something nice to qualify my sayings.
As a proud citizen of the Ghetto of Category Land,
sounds ironic and upsetting, showing that you were very upset that i consider certain characteristics of our group proper of a ghetto, in the sense of isolation from the world of real mathematics. Well, I do think that one of these characteristics is the introduction of names and terminology in an unjustified way. Andre Joyal call it "a subculture" (well, he just said there is a danger to become a subculture) which if you think a little, sounds better than "ghetto", but it is as negatively strong or even worst. I apologize to you for using that term that you had felt insulting (and I imagine some others in the list may have felt so) Your msage had an overall upsetting style, and I reacted accordingly. All the best, no hard feelings from my part. e.d. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]