Dear David, I appreciate your view. I would love to have the dictatorial power to reform the mathematical vocabulary. I dream of kicking out long words like diffeomorphism and homeomorphism. I guess that if they have persisted in mathematics, it is because everybody understand them. It is very difficult to impose a new terminology. There is a social aspect to the problem. Even if small group of peoples agree in using a new terminology, this may have little influence on the larger community. The new word may become a tag for identifying the members of a group. It may enclose its user into a sub-culture. Best, andré -------- Message d'origine-------- De: David Yetter [mailto:dyetter@math.ksu.edu] Date: dim. 19/09/2010 10:57 À: Joyal, André Cc: John Baez; categories Objet : Re: categories: Re: are fibrations evil? Dear Andre: Brevity is the usual reason for introducing new terminology. And, ultimately there is a need, as mathematics would grind to a halt if one had to write out a phrase giving the content of each concept whenever one wanted to talk about it. One may object to the jocular use of a word with a moral denotation as the name for a mathematical concept, but four characters beats 28 characters (or 31 if one counts spaces). It certainly seems desirable to have a brief name for either "invariant under equivalence" or "not invariant under equivalence". Best Thoughts, David Y. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]