"What word is used in mathematics to mean ""if and only if""?"
Precisely when If and only if If, and only if Only if Just in case (catachresis) Iff Material equivalence ↔ If & only if ⇔ Bi-implication All and only Materially equivalent
materially equivalent bi implication if and only if just in case catachresis precisely when material equivalence iff only if ⇔ if only if ↔ all and only
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WikipediaEntity
Iff