11. Existential quantifiers are dealt with by Skolemization.12. The equivalence provides a way for " moving " an existential quantifier before a universal one. 13. This gives us the existential quantifier . 14. To do so, one can use second-order existential quantifiers to arbitrarily choose a computation tableau. 15. The " let " expression may be considered as a existential quantifier which restricts the scope of the variable. 16. The term " quantifier variance " rests upon the philosophical term'quantifier', more precisely existential quantifier . 17. Tableaux are extended to first order predicate logic by two rules for dealing with universal and existential quantifiers , respectively. 18. For a concrete example, take the universal and existential quantifiers & forall; and & exist;, respectively. 19. Indefinites must sometimes be interpreted as existential quantifiers , and other times as universal quantifiers, without any apparent regularity. 20. In such a logic, one can regard the existential quantifier , for instance, as derived from an infinitary disjunction.
