Re: Relational lattice completeness

From: Mikito Harakiri <mikharakiri_nospaum_at_yahoo.com>
Date: 7 Apr 2006 12:19:52 -0700
Message-ID: <1144437592.866852.221050@e56g2000cwe.googlegroups.com>

vc wrote:
>
> What do you mean by metamathematics ?

http://en.wikipedia.org/wiki/Metamathematics

> >How about "extraordinary relations"?
>
> What about them ?

They are introduced in the link supplied.

> > http://citeseer.ist.psu.edu/hehner97relational.html

Tarski relation algebra appears not to have the union operator. Perhaps this may explain why the emphasis is on the relational division and "rational" aka "extraordinary" relations. One part which seems obviously missing is the introduction of negative relations. The equation with union operator

P \/ X = Q

has solutions only if P <= Q. Unlike equations in integers there has to be a second equation that would guarantee uniqueness of the solution

P \/ X = Q
P /\ X = 01

... Received on Fri Apr 07 2006 - 14:19:52 CDT