# Re: Can relational alegbra perform bulk operations?

From: David BL <davidbl_at_iinet.net.au>

Date: Wed, 30 Sep 2009 19:37:06 -0700 (PDT)

Message-ID: <731f17c9-d309-4ed8-8965-94822d6bbee9_at_g22g2000prf.googlegroups.com>

On Sep 30, 5:54 am, Tegiri Nenashi <tegirinena..._at_gmail.com> wrote:

Date: Wed, 30 Sep 2009 19:37:06 -0700 (PDT)

Message-ID: <731f17c9-d309-4ed8-8965-94822d6bbee9_at_g22g2000prf.googlegroups.com>

On Sep 30, 5:54 am, Tegiri Nenashi <tegirinena..._at_gmail.com> wrote:

>

*> But this is like saying that one can't define summation and**> multiplication in a ring with abstract elements. You wouldn't insist**> that any advanced algebra book had a long arithmetic introduction with**> tedious instructions how one adds and multiplies numbers (in their**> decimal representation)?*I haven't studied any of the work on formalising the RM as an algebraic structure. My understanding is that an algebraic structure typically consists of a set of abstract elements closed under one or more operators and satisfying some axioms.

I would have thought that set theory itself cannot be regarded as an algebraic structure - because it is not possible to form the set of all sets (by Russell). Operators like 'union', 'intersection' and 'element-of' don't have a domain and therefore are not functions.

Wouldn't the RM suffer from the same limitation (well at least an untyped version of the RM)?

Sorry if I'm talking about things outside my depth. Received on Wed Sep 30 2009 - 21:37:06 CDT