- From: Toby Inkster <tai@g5n.co.uk>
- Date: Wed, 06 Jan 2010 10:30:31 +0000
- To: Pat Hayes <phayes@ihmc.us>
- Cc: darood <samatar.sharmarke@gmail.com>, semantic-web@w3.org
On Tue, 2010-01-05 at 00:54 -0600, Pat Hayes wrote:
> On Jan 4, 2010, at 5:11 PM, darood wrote:
>
> > • “sister of” - Symmetric
>
> No. Mary sisterOf John, but not John sisterOf Mary.
Depending on your definition of "sister of" with regards to
step-sisters, half-sisters, sisters-in-law, etc, the relation may be
transitive though.
{ :Mary :sisterOf :John . :Anne :sisterOf :Mary . }
=> { :Anne :sisterOf :John . } .
Amongst an all-female population, sisterOf becomes a symmetric
relationship too.
A slightly broader transitive "sisterOf-or-sameAs" relationship (that
is, a definition which effectively counts each woman herself amongst her
own sisters), in an all-female population is an equivalence
relationship.
--
Toby A Inkster
<mailto:mail@tobyinkster.co.uk>
<http://tobyinkster.co.uk>
Received on Wednesday, 6 January 2010 10:31:13 UTC