Nondeterminism in algebraic specifications and algebraic programs

"Nondeterminism in Algebraic Specifications and Algebraic Programs" presents a mathematical theory for the integration of three concepts: non-determinism, axiomatic specification and term rewriting. For non-deterministic programs, an algebraic specification language is provided which admits the application of automated tools based on term rewriting techniques. This general framework is used to explore connections between logic programming and algebraic programming. Examples from various areas of computer science are given, including results of computer experiments with a prototypical implementation. This book should be of interest to readers working within several fields of theoretical computer science, from algebraic specification theory to formal descriptions of distributed systems

Foundations of Software Science and Computation Structures

This open access book constitutes the proceedings of the 24th International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2021, which was held during March 27 until April 1, 2021, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2021. The conference was planned to take place in Luxembourg and changed to an online format due to the COVID-19 pandemic. The 28 regular papers presented in this volume were carefully reviewed and selected from 88 submissions. They deal with research on theories and methods to support the analysis, integration, synthesis, transformation, and verification of programs and software systems

Böhm theorem and Böhm trees for the Lambda-mu-calculus

International audienceParigot's λμ-calculus (Parigot, 1992) is now a standard reference about the computational content of classical logic as well as for the formal study of control operators in functional languages. In addition to the fine-grained Curry-Howard correspondence between minimal classical deductions and simply typed λμ-terms and to the ability to encode many usual control operators such as call/cc in the λμ-calculus (in its historical call-by-name presentation or in call-by-value versions), the success of the λμ-calculus comes from its simplicity, its good meta-theoretical properties both as a typed and an untyped calculus (confluence, strong normalization, etc.) as well as the fact that it naturally extends Church's λ-calculus. Though, in 2001, David and Py proved that Böhm's theorem, which is a fundamental result of the untyped λ-calculus, cannot be lifted to Parigot's calculus. In the present article, we exhibit a natural extension to Parigot's calculus, the Λμ-calculus, in which Böhm's property, also known as separation property, can be stated and proved. This is made possible by a careful and detailed analysis of David and Py's proof of non-separability and of the characteristics of the λμ-calculus which break the property: we identify that the crucial point lies in the design of Parigot's λμ-calculus with a twolevel syntax. In addition, we establish a standardization theorem for the extended calculus, deduce a characterization of solvability, describe Λμ-Böhm trees and connect the calculus with stream computing and delimited control