description logic
In plain wordsA family of precise logical languages for defining categories and how they relate, such as 'a parent is a person with at least one child', designed so that a computer's reasoning about them always finishes.
Any of a group of logics for knowledge representationknowledge representation, n.: The study of how to record knowledge about objects, categories, rules and events in a precise format, so that a program can reason with it and reach conclusions nobody typed in., most of them decidable fragments of first-order logicfirst-order logic, n.: A precise formal language for statements about objects and their relations, using 'for all' and 'there exists', such as 'every person has a mother'. It is the standard logic of mathematics and of classic AI., that model a domain with three kinds of building block: individuals, concepts (classes of individuals) and roles (binary relations between them). Complex concepts are built with constructors such as intersection, union, negation and existential or universal restrictions — Parent ≡ Person ⊓ ∃hasChild.Person — and knowledge is split into a TBox of terminological axioms and an ABox of facts about individuals. Standard reasoning services check consistency, decide subsumption (whether one concept is necessarily a subclass of another), classify a whole ontologyontology, n.: A carefully defined vocabulary for a subject such as medicine, spelling out each kind of thing, how kinds nest inside one another, and which connections between them are allowed., and determine which concepts an individual belongs to. Each language trades expressiveness against computational cost, from the tractable EL family, used for the very large SNOMED CT medical terminology, to SROIQ, the basis of OWL 2. Tableau-based reasoners such as HermiT and Pellet implement these services.
Origin
Grew out of Ronald Brachman's KL-ONE system (1977–1985), a formalization of semantic networkssemantic network, n.: A way of storing knowledge as a web of concepts joined by labeled arrows, such as 'canary — is a — bird' and 'bird — can — fly', so a program can follow the links. and framesframe, n.: In classic AI, a ready-made template for a familiar kind of thing or event, such as a kitchen or a job interview, with blanks to fill in and sensible default values.. Brachman and Hector Levesque's 1984 paper on the tractability of subsumption in 'frame-based description languages' opened the study of expressiveness versus cost. The field was then often called terminological logics; 'description logics' became the standard name during the 1990s, and the W3C's Web Ontology LanguageWeb Ontology Language, prop. n.: A web standard language for writing ontologies — precise definitions of categories and their relationships — so that software can check them for contradictions and infer new facts. (2004) put it into worldwide use.
Related
- ontologyontology, n.: A carefully defined vocabulary for a subject such as medicine, spelling out each kind of thing, how kinds nest inside one another, and which connections between them are allowed.
- Web Ontology LanguageWeb Ontology Language, prop. n.: A web standard language for writing ontologies — precise definitions of categories and their relationships — so that software can check them for contradictions and infer new facts.
- first-order logicfirst-order logic, n.: A precise formal language for statements about objects and their relations, using 'for all' and 'there exists', such as 'every person has a mother'. It is the standard logic of mathematics and of classic AI.
- knowledge representationknowledge representation, n.: The study of how to record knowledge about objects, categories, rules and events in a precise format, so that a program can reason with it and reach conclusions nobody typed in.
- semantic networksemantic network, n.: A way of storing knowledge as a web of concepts joined by labeled arrows, such as 'canary — is a — bird' and 'bird — can — fly', so a program can follow the links.
- semantic websemantic web, n.: An effort to label data on the web in a standard, precise way so that programs, not only human readers, can tell what it means and connect facts drawn from many different sites.
Sources
- Brachman, R. J. & Schmolze, J. G. (1985). An Overview of the KL-ONE Knowledge Representation System. Cognitive Science 9(2), 171–216.
- Baader, F. et al. (eds.) (2003). The Description Logic Handbook. Cambridge University Press.
Mentioned in
deductive reasoningdeductive reasoning, n.: Reasoning in which true starting points guarantee a true conclusion: if every square is a rectangle and this shape is a square, then it must be a rectangle., first-order logicfirst-order logic, n.: A precise formal language for statements about objects and their relations, using 'for all' and 'there exists', such as 'every person has a mother'. It is the standard logic of mathematics and of classic AI., frameframe, n.: In classic AI, a ready-made template for a familiar kind of thing or event, such as a kitchen or a job interview, with blanks to fill in and sensible default values., knowledge representationknowledge representation, n.: The study of how to record knowledge about objects, categories, rules and events in a precise format, so that a program can reason with it and reach conclusions nobody typed in., ontologyontology, n.: A carefully defined vocabulary for a subject such as medicine, spelling out each kind of thing, how kinds nest inside one another, and which connections between them are allowed., semantic networksemantic network, n.: A way of storing knowledge as a web of concepts joined by labeled arrows, such as 'canary — is a — bird' and 'bird — can — fly', so a program can follow the links., semantic websemantic web, n.: An effort to label data on the web in a standard, precise way so that programs, not only human readers, can tell what it means and connect facts drawn from many different sites., Web Ontology LanguageWeb Ontology Language, prop. n.: A web standard language for writing ontologies — precise definitions of categories and their relationships — so that software can check them for contradictions and infer new facts.