A set of atomic literals with at most one positive literal. Usually written
L where n>=0, “conjuction (“AND”). If L is false the clause is regarded as a goal. Horn clauses can express a subset of statements of first order logic.
The name “Horn Clause” comes from the logician Alfred Horn, who first pointed out the significance of such clauses in 1951, in the article “On sentences which are true of direct unions of algebras”, Journal of Symbolic Logic, 16, 14-21.
A definite clause is a Horn clause that has exactly one positive literal.
[hawrn] /hɔrn/ noun 1. Lena, 1917–2010, U.S. singer and actress. 2. Marilyn, born 1934, U.S. mezzo-soprano.
noun a sexually excited or desirous person Usage Note slang n. by 1995, from horn (n.) in the sexual sense (see horny) + dog.
[hawrnd] /hɔrnd/ adjective 1. having (often used in combination): a horned beast; blunt-horned. 2. having or wearing a horn-shaped protuberance, ornament, or the like: the horned crags. 3. having a crescent-shaped part or form. [hawrn] /hɔrn/ noun 1. one of the bony, permanent, hollow paired growths, often curved and pointed, that project from the upper […]
noun 1. a tropical African plant, Cucumis metuliferus, having fruit with spiky, orange skin and jellylike pulp that tastes like cucumbers. 2. the fruit of this plant.