Simon Peyton Jones ([EMAIL PROTECTED]) wrote: : If someone could write a sentence or two to explain why gcd 0 0 = 0, : (ideally, brief ones I can put in the report by way of explanation), : I think that might help those of us who have not followed the details : of the discussion.
Division in the context of gcds (of integers) is usually defined along the lines of: An integer $a$ divides integer $b$ if there exists an integer $c$ such that $a c= b$. Note that here division is a *relation* an not a *function*/*operator*. Given the definition of division being a relation it makes perfect sense to say that $0$ divides $0$ which is why gcd 0 0 = 0; and gcd 0 0 /= error "Blah" The gcd of two integers is usually defined as a non-negative number to make it unique. HTH. PS: I am strongly in favour of gcd 0 0 = 0. Regards, Marc van Dongen _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
