DL, OWL, Model Theory
Linked Data, SKOS, Schema.org
$$a = b \,\longleftrightarrow\, (\forall P)(Pa = Pb)$$OWL 2 specification, 2012
“Include links to other URIs, to discover more things.”Tim Berners-Lee, 4th Linked Data principle, 2006
Everything is related to everything.
SKOS exactMatch indicates a high degree of confidence that two concepts can be used interchangeably across a wide range of information retrieval applicationsSKOS specification, 2009
“the same chemical” (
“the same product” (
owl:sameAs link requires approval
from the authority that is being linked to.
The identity relation is the smallest equivalence relation.
Every equivalence relation is also an identity relation, but w.r.t. a subset of the properties.
If A and B have the same income, I cannot infer identity.
But if I am reasoning about income groups, then they are identical.
Identity subrelations that are also equivalence relations can, in some contexts, be used i.o. the identity relation.
ns2:Nicotine〉 are the same according to the same criteria.
Identity context: A consistent collection of identity subrelations from the identity lattice
$$a = b \,\longleftrightarrow\, (\forall P)(Pa = Pb)$$