On Sunday 23 May 2010 18:24:50, R J wrote: > Correction: the theorem is > h . either (f, g) = either (h . f, h . g)
Still not entirely true, const True . either (undefined, undefined) $ undefined = True while either (const True . undefined, const True . undefined) undefined = undefined But if we ignore bottom, h . either (f, g) $ Left x = h (either (f,g) (Left x)) = h (f x) either (h . f, h . g) $ Left x = (h . f) x = h (f x) ---- h . either (f,g) $ Right y = h (either (f,g) (Right y)) = h (g y) either (h .f, h . g) $ Right y = (h . g) y = h (g y) _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
