A mapping between two ontologies O1 and O2 is a 5-tuple <id;E1;E2;n;R>, where: id is a unique identifier for a given mapping; E1;E2 are a set of entities, e.g., classes and properties of the first and the second ontology, respectively; R is a relation holding between the sets of entities E1 and E2; and n is a confidence measure in the [0;1] range that a relation R holds.

Zhdanova, A.V., Shvaiko, P.: Community-driven ontology matching. In: The Semantic Web: Research and Applications, pp. 34-49. Springer (2006) [-]