RE: ISSUE 15.24 if or iff - current state - propose to close

• From: Jeremy Carroll <jjc@hpl.hp.com>
• Date: Mon, 18 Nov 2002 20:53:51 +0100
• To: <www-webont-wg@w3.org>
• Message-ID: <MABBLGKMPIJFCKFGDBEPGEFLCBAA.jjc@hpl.hp.com>

Mike Smith said:
>Under the IFF interpretation, the following holds

> P rdfs:range A
> P rdfs:range B
> ->
> A = B

No, that's not it - and probably explains why you're seeing it differently.

The iff is not saying that

<
if

P rdfs:range A

then that
[
x P y   

iff y in A
]
>

but

<
P rdfs:range A
if and only if
[
if
x P Y
then
y in A
]
>

So for instance, for any empty property P and any class A we have
[
if
x P y
then
y in A
]
trivially
and so P rdfs:range A.

Jeremy
 

Received on Monday, 18 November 2002 14:49:55 UTC