@prefix skos: <http://www.w3.org/2004/02/skos/core#>.
@prefix dce: <http://purl.org/dc/elements/1.1/>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.

	dce:title "SKOS Extra Rules"@en;
	dce:creator "Hong Sun"@en;
	dce:contributor "Giovanni Mels, Jos De Roo"@en;
	dce:publisher "Agfa Healthcare/Belgium"@en;
	dce:description "Rules for extra SKOS constraint check"@en;
	skos:note "Rules to take constraint check for those patterns which are not explicitly stated as non-consistent in SKOS specification, but are considered as bad practice (according to SKOS)."@en;
	rdfs:seeAlso <http://eulersharp.sourceforge.net/2003/03swap/skos-rules>.

# SKOS Extra Integrity Constraints

# skos:exactMatch, skos:broaderTransitive are disjoint.
# This constraint is added according to the decision made in http://www.w3.org/2006/07/SWD/track/issues/73
# "2008-07-01: [rrs] RESOLVED: issue-73 is resolved by skos:exactMatch is disjoint with skos:broaderTransitive and skos:related -- http://www.w3.org/2008/07/01-swd-minutes.html#item05"
# SKOS Specification considers skos:exactMatch, skos:broadMatch as disjoint, corresponding constraint check rule is contained in http://eulersharp.sourceforge.net/2003/03swap/skos-rules.

{ ?x skos:exactMatch ?y. ?x skos:broaderTransitive ?y. } => @false.

# Detect the cycle in the hierarchical relation.
# "For many applications where knowledge organization systems are used, a cycle in the hierarchical relation represents a potential problem."
# However, in SKOS specification, "there is no condition requiring that skos:broaderTransitive be irreflexive. "
# Nevertheless, in the spec, it is suggested to use the form X skos:broaderTransitive X for finding cycles in the hierarchical relation.
# see details in: http://www.w3.org/TR/skos-reference/#L2484
# This rule is better use together with SKOS inference rule, e.g. http://eulersharp.sourceforge.net/2003/03swap/skos-rules

{ ?x skos:broaderTransitive ?x. } => @false.