Dan Weston wrote: > Here, "any path" means all paths, a logical conjunction: > > and [True, True] = True > and [True ] = True > and [ ] = True
Kim-Ee Yeoh wrote: > Hate to nitpick, but what appears to be some kind of a > limit in the opposite direction is a curious way of arguing > that: and [] = True. > > Surely one can also write > > and [False, False] = False > and [False ] = False > and [ ] = False ??? No. I think what Dan meant was that for all non-null xs :: [Bool], it is clearly true that: and (True:xs) == and xs -- (1) It therefore makes sense to define (1) to hold also for empty lists, and since it is also true that: and (True:[]) == True We obtain: and [] == True Since we can't make any similar claim about the conjuctions of lists beginning with False, there is no reasonable argument to the contrary. _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
