Noun
a logical relation between propositions p and q of the form `if p then q'; if p is true then q cannot be false
Source: WordNetLogical implication is represented by Peano's "Ɔ" simplified to "⊃", logical negation is symbolised by an elongated tilde, i.e., "~" (contemporary "~" or "¬"), the logical OR by "v". Source: Internet