20 Dec
1997
20 Dec
'97
2:21 p.m.
Colin's question, which essentially asks for a solution to the proportion abelian groups:groups :: abelian category:x does not of course have a unique answer. One solution was exact category and that was definitely one of the things I had in mind. In fact, I think I even said so. From my current vantage, I would add the following two properties: pointed and Mal'cev. For an equational category, that is almost enough to force a group structure (associativity is missing). I don't know how to force associativity by categorical properties, but pointed, exact and Mal'cev has to come awfully close to answering the question. Michael