On Tuesday, August 13, 2002, at 10:08 AM, Tim May wrote: > This graph, this set of vertices and edges, is a "per-ordered" set. > More than just a set, any category with the property that between any > two objects "p" and "q" there is AT MOST one arrow "p --> q" is said to > be "pre-ordered."

I meant to type "pre-ordered" in the first line above. I don't normally worry overmuch about minor typos, especially when I used the correct spelling right after the typo, but I wouldn't want anyone thinking there's some kind of "per-ordered" set! --Tim May