Defined Entity Type

Maine Farmer

Here is an example in CG and IFF of a defined entity type that was taken from the CGIF standard. We paraphrase the standard.

“A Maine-Farmer is a Farmer located in the state of Maine.”

CG

The following gives a definition for the entity type Maine-Farmer. Two versions are given.

The first version in linear form is expressed by a lambda expression for a farmer located in Maine. The symbol l (lambda) indicates that the concept Farmer is the formal parameter, and the sequence (Farmer) is the signature of the lambda expression. The type of the formal parameter is always a supertype of the newly defined type: Maine-Farmer £ Farmer.

[Concept: Maine-Farmer] ® (Def) ® [Lambda-Expression:

[Farmer: l] ® (Loc) ® [State: Maine]].

As an alternate notation in CGIF, types can be defined with the keyword type and a variable.

type Maine-Farmer(*x) is [Farmer: ?x] ® (Loc) ® [State: Maine]

IFF

The standard IFF form is closest to the first CG version.

<Object name=“Maine-Farmer”/>

<definition>

<Expression>

<Signature><Farmer pos=“1” var=“x”/></Signature>

<location src=“x” tgt=“State#Maine”/>

</Expression>

</definition>

</Object>

An alternate abbreviated IFF form, which embeds an expression within an entity type declaration, is closest to the second CG version.

<Object name="Maine-Farmer" var="x" genus="Farmer">

<Farmer id="x"><location val="State#Maine"/></Farmer>

</Object>

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Please send questions, comments and suggestions about this page to: Robert E. Kent rekent@ontologos.org

Copyright © 2000 TOC (The Ontology Consortium). All rights reserved. Revised: July 2000