ELK

ELK is Snow Owl's default description logic reasoner. In addition to being the fastest reasoner for SNOMED CT in the world, ELK provides partial support for concrete domains, which are becoming increasingly important to represent national drug dictionary extensions.

Snow Owl includes the latest ELK 0.4.3, which includes support for additional OWL EL constructs. ELK now supports EL++ restricted to safe nominals (see Practical Reasoning with Nominals in the EL Family of Description Logics) with partial support for concrete roles.

Concept constructors:

• Top concept

• Bottom concept

• Concept conjunctions

• Existential (abstract) role restrictions

• Safe nominals (ObjectHasValue)

• Preliminary support for existential restrictions on concrete roles with a nominal value (DataHasValue)

Axiom types:

• General concept inclusions (GCIs)

• Disjoint concepts

• Role hierarchies (abstract roles)

• Role transitivity, role reflexivity, and role chains (abstract roles)

• Concept assertions and role assertions