18 Feb
1992
18 Feb
'92
2:23 p.m.
Paul Taylor asks for the "correct" definition of regular monos and epis. I think a regular epi has always been an epi that appears as a coequalizer. The lemma is that if an epi has a pullback with itself then it is regular iff it is the coequalizer of the relevant pair of maps from that pullback (aka the "kernel pair", the "level", the "congruence"). But I can't imagine anyone insisting that split epis are regular only when they have kernel pairs. =========================================================================