W3C home > Mailing lists > Public > www-rdf-interest@w3.org > December 2002

space,time in KR: context, initial, final

From: Richard H. McCullough <rhm@cdepot.net>
Date: Sat, 14 Dec 2002 05:51:16 -0800
Message-ID: <000e01c2a377$e03e9a30$bd7ba8c0@rhm8200>
To: "Patrick J. Hayes" <phayes@ai.uwf.edu>
Cc: "RDF-Interest" <www-rdf-interest@w3.org>, "Richard S. Latimer" <latimer1@att.net>
1. general context 
The basic KR proposition has the form 
    at context { statement } 
Including space,time in context permits making statements which isolate & focus on space-time-independent properties.  Some statements are space-time-dependent.  The distinction is important because space-time-independent statements have wider implications. 
Example statements: 
a. Jane has sex=female 
b. Jane isa person 
c. John do walk with a limp done 
d. John do walk to the store done 
a and b are attribute and relation statements which are independent of space-time. 
c is an action statement which is independent of space-time. 
d is an action statement which depends on space-time. 

2. action initial and final characteristics 
The fundamental characteristics of all actions are: 
a. they change the properties of existents; 
b. they are performed by an entity. 
KR specifies the changes by a set of initial characteristics which exist before the action, and a set of final characteristics which exist after the action.  Initial and final characteristics may include space-time. 
Example statements: 
c. water do change from temperature=positive to temperature=0 done causes water do change from phase=liquid to phase=solid done 
d. John do walk from his house to the store done 
c is a causality statement which is independent of space-time. 
d is an action statement which depends on space-time. 

3. action contexts 
space,time specifies where,when an action occurs.  Typically, they specify the initial space,time of the action.  For some actions, they specify the final space,time. 
Example propositions: 
a. at 8 am { John do go to the store done } 
b. at 5 pm { John do finish od work done } 
a is a proposition with a context specifying the initiation of an action. 
b is a proposition with a context specifying the completion of an action. 
============ 
Dick McCullough 
knowledge := man do identify od existent done
knowledge haspart proposition list
Received on Saturday, 14 December 2002 08:51:17 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:57 GMT