- From: Christopher Welty <welty@us.ibm.com>
- Date: Thu, 18 Jul 2002 13:27:25 -0400
- To: webont <www-webont-wg@w3.org>

ISSUE 3.4: UniqueProp is a bad name Note: this issue is expanded to include, pending the resolution of issue 3.4, UnambiguousProp. Proposed Resolution: Change the name of DAML:UniqueProperty to OWL:FunctionalProperty Change the name of DAML:UnambiguousProperty to OWL:InverseFunctionalProperty Discussion/Explanation: A UniqueProp is a relation whose extension is restricted such that no object may appear more than once in the domain, i.e. the range of the relation for any given domain is unique. If R is a UniqueProp then R(a,x) ^ R(a,y) -> x=y Example: Birthdate(x,date) "Any entity with a birthday has only one." Notes: -This is equivalent to expressing a global MaxCardinality restriction on the relation. -The inverse of a uniqueProperty is an unambiguousProperty. -Birthdate(a,x) and Birthdate(b,x) does not imply anything beyond what the clauses alone imply, other than that a and b share a birthday. -This does not specify that a relation is "many to one", only that it is "x to 1" where x may, in fact, be one. An UnambiguousProp is a relation whose extension is restricted such that no object may appear more than once in the range, i.e. the domain of the relation for any given range is unique. If R is an unambiguousProp then R(a,x) ^ R(b,x) -> a=b Example: BiologicalFatherOf(x,y) "Every biological father of an entity is the only biological father of that entity" Notes: -This is equivalent to saying that the inverse of a relation is a daml:uniqueProperty. -BiologicalFatherOf(x,a) and BiologicalFatherOf(x,b) does not imply anything beyond what the clauses alone imply, other than that a and b share a father. -This does not specify that a relation is "one to many", only that it is "1 to x" where x may, in fact, be one. To specify a one:one relation, simply make a relation both unambigous and unique. -ChrisW

Received on Thursday, 18 July 2002 13:27:58 UTC