 In symbolic logic, the universal quantifier symbol formula_1 (a turned "A" in a sans-serif font, Unicode U+2200) is used to indicate universal quantification.It was first used in this way by Gerhard Gentzen in 1935, by analogy with Giuseppe Peano's formula_2 (turned E) notation for existential quantification and the later use of Peano's notation by Bertrand Russell.For example, if "P"("n") is the predicate "2·"n" > 2 + "n"" and N is the set of natural numbers, then