Willard Van Orman Quine

286 joseph s. ullian
one existential quantifier. But any algorithm for it would have been too
sophisticated for inclusion in Methods.
7. a1, ..., an need not be distinct, but in the absence of identity and function
symbols they can safely be regarded as n different elements.
8. See Henkin, op. cit.
9. Ehrenfeucht’s result is reported by Henkin, ibid.
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