# Re: curiousity of sets of no relations?

From: paul c <toledobythesea_at_oohay.ac>

Date: Sat, 10 Jun 2006 16:42:16 GMT

Message-ID: <IDCig.4878$iF6.4180_at_pd7tw2no>

> He simply defined them as the identity elements for the specific

Date: Sat, 10 Jun 2006 16:42:16 GMT

Message-ID: <IDCig.4878$iF6.4180_at_pd7tw2no>

Bob Badour wrote:

> paul c wrote:

*>
*

>> ... >> That seems a practical motivation. In terms of relations and/or set >> theory/predicate calculus can anybody give a more theoretical one?

*>*> He simply defined them as the identity elements for the specific

*> operations just as one defines any aggregate/fold of zero elements using**> the identity element for the base operation.*In other words, I'm guessing, "to make it all work/to guarantee the ops always return relations", i.e., the motivation is practical only, analogous to notions such as the "empty product" (such as in http://en.wikipedia.org/wiki/Empty_product)? If so, I think I'm content with that, e.g., thinking of the empty set as just a gizmo to enable various operations we desire.

p Received on Sat Jun 10 2006 - 18:42:16 CEST