# Re: constraints in algebra instead of calculus

Date: Tue, 19 Jun 2007 07:59:28 -0700

Message-ID: <1182265168.282522.303950_at_n15g2000prd.googlegroups.com>

On Jun 19, 12:59 am, Jon Heggland <jon.heggl..._at_idi.ntnu.no> wrote:

*> Vadim Tropashko wrote:
**> > R <AND> (R RENAME B as B') )
**> > IS
**> > R WHERE B = B'
**>
*

> > where the "IS" symbol is relational equality. Relational equality (aka

*> > "IS") provides a succinct way to say that the symmetric difference of
**> > the relations
**>
**> > R <AND> (R RENAME B as B') )
**>
**> > and
**>
**> > R WHERE B = B'
**>
**> > is empty.
**>
**> Forgive me if I'm not paying attention, but why do you need a special
**> symbol and explanation for relational equality? Why can't you just use =?
*

What is the syntax to disambigute the relational equality from the equality symbol in the identity relation? OK, extra brakets would do, so how about this:

( R <AND> (R RENAME B as B') ) ) = (R <AND> (B = B')) Received on Tue Jun 19 2007 - 16:59:28 CEST