On a Relative Computability Notion for Real Functions

  • Dimiter Skordev
  • Ivan Georgiev
Part of the Lecture Notes in Computer Science book series (LNCS, volume 6735)


For any class of total functions in the set of natural numbers, we define what it means for a real function to be conditionally computable with respect to this class. This notion extends a notion of relative uniform computability of real functions introduced in a previous paper co-authored by Andreas Weiermann. If the given class consists of recursive functions then the conditionally computable real functions are computable in the usual sense. Under certain weak assumptions about the class in question, we show that conditional computability is preserved by substitution, that all conditionally computable real functions are locally uniformly computable, and that the ones with compact domains are uniformly computable. All elementary functions of calculus turn out to be conditionally computable with respect to one of the small subrecursive classes.


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    Skordev, D., Weiermann, A., Georgiev, I.: \({\cal M}^2\)-computable real numbers. J. Logic Comput. (Advance Access published September 21, 2010) doi:10.1093/logcom/exq050Google Scholar
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    Skordev, D.: Uniform computability of real functions. In: Collection of Summaries of Talks Delivered at the Scientific Session on the Occasion of the 120th Anniversary of FMI, Sofia, October 24 (2009) (to appear)Google Scholar
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Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Dimiter Skordev
    • 1
  • Ivan Georgiev
    • 2
  1. 1.Faculty of Mathematics and InformaticsSofia UniversitySofiaBulgaria
  2. 2.Faculty of Natural SciencesAssen Zlatarov UniversityBurgasBulgaria

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