Note: Many use cases illustrate the desirability for Reflexivity, Irreflexivity, Asymmetry or Local Relexivity. The usefulness of these features was explicitly mentioned by the Health Care and Life Sciences interest group in their last call comment. The Semantic Web Deployment Working Group (SWD) also explicitly mentioned the potential usefulness of reflexivity and asymmetry e.g., for specifying application-specific specializations of SKOS semantic relations (see comment from the SWD). For example, in mereology, the partOf relation is defined to be transitive, reflexive, and antisymmetric. Many applications, which describe complex structures, in life science or systems engineering, require extensive use of part-whole relations, axiomatized in that way. Other relations encountered in ontology modeling require such axiomatizations as well, possibly with different characteristics (e.g., [OBO] [RO]). Examples include proper part of and locative relations (typically transitive and irreflexive), causal relations (typically transitive and irreflexive) and membership relations (typically irreflexive). Another example is the skos:broader relationship. SKOS specification [SKOS] makes no statements regarding the reflexivity or irreflexivity of skos:broader to allow both interpretations: for example it should be considered reflexive for a direct translation of an inferred OWL subclass hierarchy, but irreflexive for most thesauri or classification schemes. OWL 2 reflexivity/irreflexivity allows to add one of these two features on demand. Self restrictions are even more fine grained, allowing to state that skos:broader should only be locally reflexive or irreflexive w.r.t. skos:Concept (via a SubClassOf axiom ) .