# definite clause

## English

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### Noun

definite clause (plural definite clauses)

1. (logic) A Horn clause with exactly one positive literal.
The clauses $\neg p \vee q$, $\neg p \vee \neg q \vee r$, and $\neg p \vee \neg q \vee \neg r \vee s$ are examples of definite clauses. At least in classical logic these would be equivalent to the formulae $p \rightarrow q$, $(p \wedge q) \rightarrow r$, and $(p \wedge q \wedge r) \rightarrow s$, respectively.