Re: cdt glossary [Graph] (was: what are keys and surrogates?)
From: Marshall <marshall.spight_at_gmail.com>
Date: Fri, 11 Jan 2008 10:17:29 -0800 (PST)
Message-ID: <776af341-7e79-4426-a354-8e4fdaf1a724_at_f47g2000hsd.googlegroups.com>
> A function is definitely a type of relation (albeit a binary one). A
> function is defined as (D, C, G) where G is a subset of the cartesian
> product of DxC, just like all binary relations. However a function is
> restricted such that a member of D may only appear as the first
> element of a single ordered pair in G. I have never personally seen
> any disagreement or confusion over these definitions in mathematics.
Date: Fri, 11 Jan 2008 10:17:29 -0800 (PST)
Message-ID: <776af341-7e79-4426-a354-8e4fdaf1a724_at_f47g2000hsd.googlegroups.com>
On Jan 11, 5:17 am, JOG <j..._at_cs.nott.ac.uk> wrote:
>
> A function is definitely a type of relation (albeit a binary one). A
> function is defined as (D, C, G) where G is a subset of the cartesian
> product of DxC, just like all binary relations. However a function is
> restricted such that a member of D may only appear as the first
> element of a single ordered pair in G. I have never personally seen
> any disagreement or confusion over these definitions in mathematics.
(However Jim probably runs with a classier set of people than the worst of sci.math, boy howdy.)
Marshall Received on Fri Jan 11 2008 - 19:17:29 CET