Re: RM formalism supporting partial information
From: David BL <davidbl_at_iinet.net.au>
Date: Thu, 15 Nov 2007 21:07:36 -0800 (PST)
Message-ID: <e463cc64-6dde-4880-a079-60727279f8cb_at_d4g2000prg.googlegroups.com>
Date: Thu, 15 Nov 2007 21:07:36 -0800 (PST)
Message-ID: <e463cc64-6dde-4880-a079-60727279f8cb_at_d4g2000prg.googlegroups.com>
On Nov 16, 10:51 am, David BL <davi..._at_iinet.net.au> wrote:
> From your middle two examples we have
>
> r1 = { (x1={}, x2={}) }
> r2 = { (x1={a}, x2={}) }
>
> Then taking various interpretations of projections...
>
> I(proj({},r1)) = {}
> I(proj({},r2)) = {}
>
> I(proj({x1},r1)) = {}
> I(proj({x1},r2)) = { (x1=a) }
>
> I(proj({x2},r1)) = {}
> I(proj({x2},r2)) = {}
>
> I(proj({x1,x2},r1)) = {}
> I(proj({x1,x2},r2)) = {}
That was a bit lazy. I should be using the (tau) function to map a relation to its body. Received on Fri Nov 16 2007 - 06:07:36 CET