29,872 research outputs found
Local Induction and Provably Total Computable Functions: A Case Study
Let IΠ−2 denote the fragment of Peano Arithmetic obtained by restricting the induction scheme to parameter free Π2 formulas. Answering a question of R. Kaye, L. Beklemishev showed that the provably total computable functions (p.t.c.f.) of IΠ−2 are, precisely, the primitive recursive ones. In this work we give a new proof of this fact through an analysis of the p.t.c.f. of certain local versions of induction principles closely related to IΠ−2 . This analysis is essentially based on the equivalence between local induction rules and restricted forms of iteration. In this way, we obtain a more direct answer to Kaye’s question, avoiding the metamathematical machinery (reflection principles, provability logic,...) needed for Beklemishev’s original proof.Ministerio de Ciencia e Innovación MTM2008–0643
Polylogarithmic Cuts in Models of V^0
We study initial cuts of models of weak two-sorted Bounded Arithmetics with
respect to the strength of their theories and show that these theories are
stronger than the original one. More explicitly we will see that
polylogarithmic cuts of models of are models of
by formalizing a proof of Nepomnjascij's Theorem in such cuts. This is a
strengthening of a result by Paris and Wilkie. We can then exploit our result
in Proof Complexity to observe that Frege proof systems can be sub
exponentially simulated by bounded depth Frege proof systems. This result has
recently been obtained by Filmus, Pitassi and Santhanam in a direct proof. As
an interesting observation we also obtain an average case separation of
Resolution from AC0-Frege by applying a recent result with Tzameret.Comment: 16 page
Theological Implications of the Simulation Argument
Nick Bostrom’s Simulation Argument (SA) has many intriguing theological implications. We work out some of them here. We show how the SA can be used to develop novel versions of the Cosmological and Design Arguments. We then develop some of the affinities between Bostrom's naturalistic theogony and more traditional theological topics. We look at the resurrection of the body and at theodicy. We conclude with some reflections on the relations between the SA and Neoplatonism (friendly) and between the SA and theism (less friendly)
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