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A quantifier is a special type of Cyc constant used in quantification. CycL contains four quantifiers, represented in the Cyc Knowledge Base as instances of #$Quantifier: #$forAll, #$thereExists, #$forAllVars, and #$thereExistVars.

Each quantifier introduces one or more new variables.

#$forAllVars is shorthand for a series of nested #$forAll expressions. For example,

(forAllVars (?X ?Y ?Z) )

is shorthand for

(forAll ?X
   (forAll ?Y
     (forAll ?Z

The relationship between #$thereExistVars and #$thereExists is analogous.

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