Dear Ronnie, I totally agree with what you wrote. I wrote ------------------------------------------------------------ One lies in the fact that equivalent categories are considered to be the "same", ------------------------------------------------------------- I was careful not to write ------------------------------------------------------------ One lies in the fact that equivalent categories are considered to be the same, ------------------------------------------------------------- Sorry for not been clear enough. I hope this settle our apparent disagreement. Best, André -------- Message d'origine-------- De: Ronnie Brown [mailto:ronnie.profbrown@btinternet.com] Date: sam. 22/05/2010 17:43 À: Joyal, André Cc: Urs Schreiber; categories@mta.ca Objet : Re: RE : categories: Re terminology: Dear André There seems to me to be a tremendous amount of great work going on higher category theory, but when you write ----------------------------------------------------- One lies in the fact that equivalent categories are considered to be the "same", even if [or] when they are not isomorphic. ----------------------------------------- this seems to go against the grain of what I have been doing in groupoids since I decided they were valuable in about 1965! It sounds like the old canard `groupoids reduce to groups', so there must be some confusion in my mind on what you are saying. .... [For admin and other information see: http://www.mta.ca/~cat-dist/ ]