One of the operations exists 
(called the existential
quantifier) or for all 
(called the universal
quantifier, or sometimes, the general quantifier). However, there also exist
more exotic branches of logic which use quantifiers other than these two.
See also
Bound Variable, Existential Quantifier, Exists, For All, Free, Quantified System, Quantifier Elimination, Universal Quantifier
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References
Hall, C. and O'Donnell, J. "Computing with Quantifiers." ยง3.2 in Discrete Mathematics Using a Computer. London:Springer-Verlag, pp. 98-100, 2000.
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Cite this as:
Weisstein, Eric W. "Quantifier." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Quantifier.html