<logic> To add a quantifier to a wff so that it either binds previously free variables, or binds new variables substituted for constants.
See bound variables, free variables, instantiation, quantifier
Existential generalization
To generalize using the existential quantifier. For example to move from propositional functions like Px or propositions like Pa to (Ex)Px; from "x is purple" or "alabaster is purple" to "something is purple". Valid without restriction.
Universal generalization
To generalize using the universal quantifier. For example to move from propositional functions like Px or propositions like Pa to (x)Px; from "x is purple" or "alabaster is purple" to "everything is purple". Valid only under several restrictions.
[Glossary of First-Order Logic]
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