# KEHOME/knowledge/TheoryFormalConceptAnalysis/devlin.txt
# 1999/1/1
# new syntax Sep/29/2002



Subject: Situation Theory and Knowledge Explorer
From: Dick McCullough
To: Keith Devlin

The purpose of this short note is to present a high-level comparison
of your Situation Theory and my Knowledge Representation language.
Situation Theory:
	situation  |=  infon
KR language:
	at space,time,view  sentence

1. Your "situation" and my "view" are essentially the same --
   a specification of the context of knowledge.
2. My "sentence" is either "statement" or "question" or "command".
   Your "infon" and my "statement" are essentially the same --
   a specification of the relational units of knowledge.
3. We both consider space,time to be arguments of relations.
   I also consider space,time to be the context of actions.

4. I give special treatment to these fundamental relations:
	hierarchy - of entities and their relations
		e.g.: man isa animal; identify isa action
	definition - genus and differentia of concepts
		e.g.: man is animal with identify
	attribute - static characteristics of entities
		e.g.: Keith has sex=male
	action - changes in attributes of entities
		e.g.: Dick do walk from x to y done
5. I associate "format" and "meaning" attributes with each relation.
   "meaning" is essentially a procedure -- a sequence of statements
   that specifies the meaning of a relational unit in a context.
   e.g.: birth is relation with
	format=[space:1, time:2, sex:3, person:4, person:5, person:6],
	meaning={$4 has birthplace=$1, birthday=$2, sex=$3,
		mother=$5, father=$6}