A Characterization of Polynomial Time Computable Functions from the Integers to the Reals Using Discrete Ordinary Differential Equations.

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Title: A Characterization of Polynomial Time Computable Functions from the Integers to the Reals Using Discrete Ordinary Differential Equations.
Authors: Blanc, Manon1,2 (AUTHOR) manon.blanc@lix.polytechnique.fr, Bournez, Olivier1 (AUTHOR) olivier.bournez@lix.polytechnique.fr
Source: International Journal of Foundations of Computer Science. Nov2025, Vol. 36 Issue 7, p989-1016. 28p.
Subjects: Computable functions, Computable analysis, Ordinary differential equations, Linear differential equations, Polynomial time algorithms, Mathematical functions, Computational complexity
Abstract: In a recent article, the class of functions from the integers to the integers computable in polynomial time has been characterized using discrete ordinary differential equations (ODE), also known as finite differences. Doing so, the authors pointed out the fundamental role of linear (discrete) ODEs and classical ODE tools such as changes of variables to capture computability and complexity measures, or as a tool for programming. In this article, we extend the approach to a characterization of functions from the integers to the reals computable in polynomial time in the sense of computable analysis. In particular, we provide a characterization of such functions in terms of the smallest class of functions that contains some basic functions, and that is closed by composition, linear length ODEs, and a natural effective limit schema. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:In a recent article, the class of functions from the integers to the integers computable in polynomial time has been characterized using discrete ordinary differential equations (ODE), also known as finite differences. Doing so, the authors pointed out the fundamental role of linear (discrete) ODEs and classical ODE tools such as changes of variables to capture computability and complexity measures, or as a tool for programming. In this article, we extend the approach to a characterization of functions from the integers to the reals computable in polynomial time in the sense of computable analysis. In particular, we provide a characterization of such functions in terms of the smallest class of functions that contains some basic functions, and that is closed by composition, linear length ODEs, and a natural effective limit schema. [ABSTRACT FROM AUTHOR]
ISSN:01290541
DOI:10.1142/S0129054124470014