1 Nov
1993
1 Nov
'93
11:02 p.m.
What do you call it if you have a category C, and you have a class X of arrows of C such that if x in X, then gxf in X for all composable isomorphisms f and g?
I haven't seen a name, but can I suggest calling X a "2-sided sieve"? (Or "2-sided crible"?) Conceivably, people who know what a sieve is could hazzard a guess at what "2-sided sieve" means. Steve Vickers. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++