David's trick

1997/12/06 by Sy D. Friedman, Friedman, Sy D.
Computer Science · #Advanced Algebra and Logic #Computability, Logic, AI Algorithms #FOS: Mathematics #Logic (math.LO) #Logic, Reasoning, and Knowledge

paper · pdf · doi:10.48550/arxiv.math/9712273

openalex publication_date 1997/12/06 · openalex created_date 2022/09/09 · openalex updated_date 2026/07/28

Abstract

We put into a general setting a technique of Rene' David (see "A Very Absolute Pi¹₂ Singleton, Annals of Pure and Applied Logic, 1982) to show that for S a Sigma¹₁ statement quantifying over subclasses of V of a special form, there is a stronger Sigma¹₃ statement quantifying over reals which can be forced over any model of S. Then I mention some application to Pi¹₂ Singletons and to Sigma¹₃ absoluteness.

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