12 Mar
1996
12 Mar
'96
3:27 p.m.
On Mike Barr's comments. The bulk of them are right enough, though maybe it is not quite fair to complain that something designed as foundation for every- thing is awkward to work with. Like complaining that the tax code is full of qualifications and exceptions. But, what stirred me to respond is recognition of an old friend in <<I would like to say that a fraction is a pair of integers m/n, n > 0 and <<that m/n = p/q when mq = np.>> So would Saunders MacLane, sorry, Mac Lane. He gives the axioms in his 1948 invited address published as 'Duality for groups' in BullAMS 1950. The community has not taken up Saunders' axioms, can't think why. John Isbell