Definition:Universal Quantifier/Historical Note

From ProofWiki
Jump to navigation Jump to search

Historical Note on Universal Quantifier

The symbol $\forall$ for the universal quantifier was first used by Gerhard Karl Erich Gentzen in 1935: Untersuchungen über das logische Schließen. II (Math. Z. Vol. 39 (3): pp. 405 – 431).

He invented it in analogy with the existential quantifier symbol $\exists$ which he borrowed from Bertrand Russell.

Russell himself used the notation $\paren x$ for for all $x$. See his 1908: Mathematical Logic as Based on the Theory of Types (Amer. J. Math. Vol. 30: pp. 222 – 262).


Sources