Op 2006-01-10, Christopher Subich schreef <[EMAIL PROTECTED]>: > Antoon Pardon wrote: >> Op 2006-01-10, Peter Decker schreef <[EMAIL PROTECTED]>: > >>>I don't see the two comparisons as equivalent at all. If two things >>>are different, it does not follow that they can be ranked. >> >> >> That a < b returns false doesn't imply that a and b can be ranked. >> take sets. set([1,2]) and set([1,3)) can't be ranked but >> set([1,2]) < set([1,3)) returns False just as set([1,2]) > set([1,3)) >> does. > > Breaking my resolution already, but you're ignoring the fact that the > set type uses the '<' and '>' operators from a set-theoretic, not > number-theoretic point of view.
That is irrelevant. the '<' and '>' symbols are usable to denote any mathematical order and are often enough used for even other order relations. The only reason that other symbols like the subset symbol are used is to avoid confusion about which order you are talking because numbers and sets are used together often enough. But the superset relationship is mathematically just as much an order relation as is the greater than relationship. > Saying "set(1,3) is greater than > set(1,2)" is meaningless (and not false), because the mathematical basis > of the operator in this context is superset -- "set(1,3) is a superset > of set(1,2)" is well-defined and false. No it is not meaningless. The superset relationship is just as much an order relationship and thus can mathematically make use of the '<' and '>' symbol just as any mathematical order relation can. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list