Yu, X., Riesz representation theorem, Borel measures and subsystems of second-order arithmetic, Annals of Pure and Applied Logic 59 65-78. Formalized concept of finite Borel measures is developed in the language of second-order arithmetic. Formalization of the Riesz representation theorem is proved to be equivalent to arithmetical comprehension. Codes of Borel sets of complete separable metric spaces are defined and proved to be meaningful in the subsystem ATR0. Arithmetical transfinite recursion is enough to prove the measurability of Borel sets for (...) any finite Borel measure on a compact complete separable metric space. (shrink)

Arithmetical comprehension is proved to be equivalent to the enumerability of singular points of any measure on the Cantor space. It is provable in ACA0 that any perfect closed subset of [0, 1] is the support of some continuous positive linear functional on C[0, 1].

After sketching the main lines of Hilbert's program, certain well-known andinfluential interpretations of the program are critically evaluated, and analternative interpretation is presented. Finally, some recent developments inlogic related to Hilbert's program are reviewed.

Traces the development of recursive functions from their origins in the late nineteenth century to the mid-1930s, with particular emphasis on the work and influence of Kurt Gödel.

In 1958 Gödel published his Dialectica interpretation, which reduces classical arithmetic to a quantifier-free theory T axiomatizing the primitive recursive functionals of finite type. Here we extend Gödel's T to theories Pn of “predicative” functionals, which are defined using Martin-Löf's universes of transfinite types. We then extend Gödel's interpretation to the theories of arithmetic inductive definitions IDn, so that each IDn is interpreted in the corresponding Pn. Since the strengths of the theories IDn are cofinal in the ordinal Γ0, as (...) a corollary this analysis provides an ordinal-free characterization of the <Γ0-recursive functions. (shrink)

Solovay has shown that if $\cal{O}$ is an open subset of $P(\omega)$ with code $S$ and no infinite set avoids $\cal{O}$ , then there is an infinite set hyperarithmetic in $S$ that lands in $\cal{O}$ . We provide a direct proof of this theorem that is easily formalizable in $ATR_0$.