Title
Affine functions and series with co-inductive real numbers
Abstract
We extend the work of A. Ciaffaglione and P. di Gianantonio on the mechanical verification of algorithms for exact computation on real numbers, using infinite streams of digits implemented as a co-inductive type. Four aspects are studied. The first concerns the proof that digit streams correspond to axiomatised real numbers when they are already present in the proof system. The second re-visits the definition of an addition function, looking at techniques to let the proof search engine perform the effective construction of an algorithm that is correct by construction. The third concerns the definition of a function to compute affine formulas with positive rational coefficients. This is an example where we need to combine co-recursion and recursion. Finally, the fourth aspect concerns the definition of a function to compute series, with an application on the series that is used to compute Euler's number e. All these experiments should be reproducible in any proof system that supports co-inductive types, co-recursion and general forms of terminating recursion; we used the COQ system (Dowek et al. 1993; Bertot and Castéran 2004; Giménez 1994).
Year
DOI
Venue
2007
10.1017/S0960129506005809
Mathematical Structures in Computer Science
Keywords
DocType
Volume
affine function,real number,co-inductive type,effective construction,axiomatised real number,addition function,affine formula,proof search engine,coq system,co-inductive real number,proof system,p. di gianantonio
Journal
17
Issue
ISSN
Citations 
1
Mathematical Structures in Computer Science 17, 1 (2006)
14
PageRank 
References 
Authors
0.82
21
1
Name
Order
Citations
PageRank
Yves Bertot144240.82