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seen Nov 12 '12 at 19:09

Nov
12
comment The opposite functor
Intuitively, the "id-condition" of the above functor is easy to see and, in the hunt for a formal justification, I already have a by case analysis (so ugly!) one. The "contra-contravariant" is the one can't see, even informally. Could you spare another hint on this? Thanks anyway.
Nov
11
asked The opposite functor
Nov
10
awarded  Scholar
Nov
10
comment Opposite category functor
@Hurkyl: and before posting this question, I was looking at $Mat$, the category of matrices. Just to be sure, in this case it is true that $Mat^{\text{op}} = Mat$, right?
Nov
10
accepted Opposite category functor
Nov
10
comment Opposite category functor
@Andrew: Thanks, for giving an example helped me "see it".
Nov
10
comment Opposite category functor
@QiaochuYuan: You're right, "always" should not be there. Thanks for noticing it.
Nov
10
awarded  Student
Nov
10
asked Opposite category functor