Mechanizing Nonstandard Real Analysis

This paper first describes the construction and use of the hyperreals in the theorem-prover Isabelle within the framework of higher-order logic (HOL). The theory, which includes infinitesimals and infinite numbers, is based on the hyperreal number system developed by Abraham Robinson in his nonstandard analysis (NSA). The construction of the hyperreal number system has been carried out strictly through the use of definitions to ensure that the foundations of NSA in Isabelle are sound. Mechanizing the construction has required that various number systems including the rationals and the reals be built up first. Moreover, to construct the hyperreals from the reals has required developing a theory of filters and ultrafilters and proving Zorn's lemma, an equivalent form of the axiom of choice. This paper also describes the use of the new types of numbers and new relations on them to formalize familiar concepts from analysis. The current work provides both standard and nonstandard definitions for the various notions, and proves their equivalence in each case. To achieve this aim, systematic methods, through which sets and functions are extended to the hyperreals, are developed in the framework. The merits of the nonstandard approach with respect to the practice of analysis and mechanical theorem-proving are highlighted throughout the exposition.

[1]  Alonzo Church,et al.  A formulation of the simple theory of types , 1940, Journal of Symbolic Logic.

[2]  A. Robinson Non-standard analysis , 1966 .

[3]  Andrew M. Gleason,et al.  Fundamentals of Abstract Analysis , 2018 .

[4]  H. Burkill,et al.  A second course in mathematical analysis , 1970 .

[5]  H. Keisler Foundations of infinitesimal calculus , 1976 .

[6]  J. Conway On Numbers and Games , 1976 .

[7]  K. D. Stroyan,et al.  Introduction to the theory of infinitesimals , 1976 .

[8]  W. W. Bledsoe,et al.  Automatic Proofs of Theorems in Analysis Using Nonstandard Techniques , 1977, JACM.

[9]  Richard Vesley An intuitionistic infinitesimal calculus , 1981 .

[10]  Philip J. Davis,et al.  The Mathematical Experience , 1982 .

[11]  Detlef Laugwitz Infinitely small quantities in Cauchy's textbooks , 1987 .

[12]  Nigel J. Cutland,et al.  Nonstandard Analysis and its Applications , 1988 .

[13]  Ton Lindstrøm Nonstandard Analysis and its Applications: AN INVITATION TO NONSTANDARD ANALYSIS , 1988 .

[14]  A. Simpson The infidel is innocent , 1990 .

[15]  M. Gordon,et al.  Introduction to HOL: a theorem proving environment for higher order logic , 1993 .

[16]  John Harrison,et al.  Constructing the real numbers in HOL , 1992, Formal Methods Syst. Des..

[17]  van Ls Bert Benthem Jutting,et al.  Checking Landau's “Grundlagen” in the Automath System: Appendices 3 and 4 (The PN-lines; Excerpt for “Satz 27”) , 1994 .

[18]  Lawrence Charles Paulson,et al.  Isabelle: A Generic Theorem Prover , 1994 .

[19]  Patrick Suppes,et al.  Free-variable axiomatic foundations of infinitesimal analysis: A fragment with finitary consistency proof , 1995, Journal of Symbolic Logic.

[20]  Michael Beeson Using Nonstandard Analysis to Ensure the Correctness of Symbolic Computations , 1995, Int. J. Found. Comput. Sci..

[21]  John Robert Harrison,et al.  Theorem proving with the real numbers , 1998, CPHC/BCS distinguished dissertations.

[22]  Eric Schechter,et al.  Handbook of Analysis and Its Foundations , 1996 .

[23]  Claude Kirchner,et al.  Automated Deduction — CADE-15 , 1998, Lecture Notes in Computer Science.

[24]  Lawrence C. Paulson,et al.  The Inductive Approach to Verifying Cryptographic Protocols , 2021, J. Comput. Secur..

[25]  Edmund Landau,et al.  Foundations of analysis , 2001 .

[26]  Jacques Fleuriot A Combination of Geometry Theorem Proving and Nonstandard Analysis with Application to Newton's Principia , 2001 .