RE: SUO: -- Technical Methodology
Dear John,
I agree. This is what necessarily being in space-time but not
necessarily having to know where means for me.
Matthew West
Principal Consultant
Shell Information Technology International Limited
Shell Centre, London SE1 7NA, United Kingdom
Tel: +44 20 7934 4490 Other Tel: +44 7796 336538
Email: matthew.west@shell.com
Internet: http://www.shell.com
> -----Original Message-----
> From: John F. Sowa [mailto:sowa@bestweb.net]
> Sent: 18 June 2003 17:06
> To: West, Matthew R SITI-ITPSIE
> Cc: Patrick Cassidy; standard-upper-ontology@ieee.org
> Subject: Re: SUO: -- Technical Methodology
>
>
> Dear Matthew,
>
> Just one qualification:
>
> > MW: Petri nets deal with classes of activity/process
> > rather than particular ones, so they deal with valid
> > patterns of activity which will be atemporal.
>
> It is true that a Petri net, as a specification, is
> atemporal. But a Petri net marked with tokens that are
> in the process of "firing" exists in space and time.
>
> The main point I wanted to make is that the processes
> created by the firing of the transitions in a Petri net
> are defined in a way that makes no reference to either
> space or time.
>
> They exist in space-time, but they do not depend on any
> metric for space or time. In fact, I would prefer to
> say that metric time is a convention that is defined by
> a clock, which can be specified by a suitably designed
> Petri net. That way of talking makes causal dependency
> more fundamental to the ontology than temporal precedence.
>
> John
>
>