Delta-Decidability over the Reals

  • Authors:
  • Sicun Gao;Jeremy Avigad;Edmund M. Clarke

  • Affiliations:
  • -;-;-

  • Venue:
  • LICS '12 Proceedings of the 2012 27th Annual IEEE/ACM Symposium on Logic in Computer Science
  • Year:
  • 2012

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Abstract

Given any collection F of computable functions over the reals, we show that there exists an algorithm that, given any sentence A containing only bounded quantifiers and functions in F, and any positive rational number delta, decides either "A is true", or "a delta-strengthening of A is false". Moreover, if F can be computed in complexity class C, then under mild assumptions, this "delta-decision problem" for bounded Sigma_k-sentences resides in Sigma_k(C). The results stand in sharp contrast to the well-known undecidability of the general first-order theories with these functions, and serve as a theoretical basis for the use of numerical methods in decision procedures for formulas over the reals.