Re: On on

On Thu, 02 Nov 2006, Nils Anders Danielsson wrote:

Do you consider on to be above or below the Fairbairn threshold, by the way? I think it is above the threshold since * we get rid of two lambdas, * we get rid of the duplication of p, * and, most importantly, it is easier at a glance to tell what the function does (assuming one knows about on).

And now Ulf is in the process of proving that flip on is a functor from C to C^op for any CCC C, with flip on defined as follows: flip_on_A(B) = (A^B)^B flip_on_A(f) = curry (curry (eval ∘ id × f) ∘ eval ∘ id × f) Ulf might follow up with a proof. :) -- /NAD