Re: Requirements for update languages?
Date: Fri, 15 Nov 2002 13:49:31 +0200
Message-ID: <3DD4DF4B.1C26A696_at_atbusiness.com>
Jan Hidders wrote:
> Lauri Pietarinen wrote:
> >> >
> >> > B1 x B2 = { ( x, n+m ) | (x, n) in B1, (x, m) in B2 }
> >>
> >> Ahem, that should of course be n.m, i.e., n times m, and not n+m. :-(
> >
> >Yes, it did look a bit strange...
> >
> >But just to clarify things, n and m are cardinalities, right?
> >
> >B1 = {(0,2 )} and B2 = {(1,1),(2,1)}
> >
> >if applied to the original example?
> >
> >But these are sets? So what do they have to do
> >with bags?
>
> They are bags, or, to be more precies, that's how bags are usually defined:
> functions that map some set to the set of natural numbers, and functions in
> turn are usually defined as binary relations that are functional and total.
> And, yes, that confirms Date's point.
regards,
Lauri Pietarinen
Received on Fri Nov 15 2002 - 12:49:31 CET