Single Idea 13909

[catalogued under 4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / a. Symbols of PC]

Full Idea

Just as '(∀x)(...)' is to mean 'take any x: then....', so we write '(∃x)(...)' to mean 'there is an x such that....'

Gist of Idea

Write '(∀x)(...)' to mean 'take any x: then...', and '(∃x)(...)' to mean 'there is an x such that....'

Source

E.J. Lemmon (Beginning Logic [1965], 3.1)

Book Reference

Lemmon,E.J.: 'Beginning Logic' [Nelson 1979], p.96


A Reaction

[Actually Lemmon gives the universal quantifier symbol as '(x)', but the inverted A ('∀') seems to have replaced it these days]