1,958,935 research outputs found
Isabelle Primer for Mathematicians
No full textThis is a quick introduction to the Isabelle/HOL proof assistant, aimed at mathematicians who would like to use it for the formalization of mathematical results
Verification of Refactorings in Isabelle/HOL
No full textRefactorings are source-to-source behaviour-preserving program transformations that are used for improving program structure. Programmers refactor code to adapt it when new functionality is added or when the code is being repaired -- refactoring serves to keep the code ``clean'' and more maintainable. Refactoring can also be used as an exploratory technique for understanding source code. The process of refactoring has been automated through the implementation of tools; these tools assist programmers by handling the consistent application of behaviour-preserving changes to the code. It is desirable that the implementations of refactorings are correct: bugs might otherwise be introduced in refactored programs. The correctness, i.e. behaviour-preservation, of refactoring is traditionally probed by testing the refactored program and not the refactoring implementation directly. Recently, automated testing techniques have been used to test implementations of refactorings directly, but the coverage of testing is partial at best. The verification of refactorings is more challenging but determines whether a refactoring is behaviour-preserving for all possible programs. We study the verification of refactorings using the proof assistant Isabelle/HOL for untyped and typed lambda-calculi. Some of the issues encountered during verification are technical rather than purely theoretical: they relate to the embedding of the programming language in the proof environment. The reasons for our choice of techniques are discussed. We also discuss other practical considerations such as the readability of mechanised refactorings, and the avoidance of computationally expensive refactorings
Cut-elimination, substitution and normalisation
No full textDate of Acceptance: 01/2015We present a proof (of the main parts of which there is a formal version, checked with the Isabelle proof assistant) that, for a G3-style calculus covering all of intuitionistic zero-order logic, with an associated term calculus, and with a particular strongly normalising and confluent system of cut-reduction rules, every reduction step has, as its natural deduction translation, a sequence of zero or more reduction steps (detour reductions, permutation reductions or simplifications). This complements and (we believe) clarifies earlier work by (e.g.) Zucker and Pottinger on a question raised in 1971 by Kreisel.Peer reviewe
Generating inductive verification proofs for Isabelle using the partial evaluator Ecce
No full textEcce is a partial deduction system which can be used to automatically generate abstractions for the model checking of many infinite state systems. We show that to verify the abstractions generated by Ecce we may employ the proof assistant Isabelle. Thereby Ecce is used to generate the specification, hypotheses and proof script in Isabelle's theory format. Then, in many cases, Isabelle can automatically execute these proof scripts and thereby verify the soundness of Ecce's abstraction. In this work we focus on the specification and verification of Petri nets
Isabelle Noth über die Krise in der reformierten Kirche
No full textWarum ist Gottfried Locher Ende Mai als Präsident der Evangelisch-reformierten Kirche zurückgetreten? Was steckt hinter den Vorwürfen, Locher habe «Grenzverletzungen» begangen? Diese Fragen haben in den letzten Wochen die Reformierte-evangelische Kirche Schweiz beschäftigt und in eine tiefe Krise gestürzt. Gestern hat die Synode, das Parlament der Kirche, getagt. Der Tag war mit Spannung erwartet worden, viele offene Fragen sollten endlich geklärt werden. Gelungen ist dies nur zum Teil. Denn neue Enthüllungen über eine heimliche Affäre zwischen Gottfried Locher und einem weiteren Mitglied der Kirchenleitung wurden publik. Diese Affäre verkompliziert auch die Aufklärung der Vorwürfe gegen Gottfried Locher. Wie findet die Evangelisch-reformierte Kirche aus dieser Krise wieder heraus? Wie sehr schadet das alles der Kirche als Institution? Wir haben die Berner Theologieprofessorin Isabelle Noth dazu befragt. Sie ist Co-Direktorin des Instituts für Praktische Theologie an der Universität Bern. Barbara Peter hat mit ihr gesprochen
Inductive theorem proving by program specialisation: Generating proofs for Isabelle using Ecce (Invited talk)
No full textIn this paper we discuss the similarities between program specialisation and inductive theorem proving, and then show how program specialisation can be used to perform inductive theorem proving. We then study this relationship in more detail for a particular class of problems (verifying infinite state Petri nets) in order to establish a clear link between program specialisation and inductive theorem proving. In particular, we use the program specialiser Ecce to generate specifications, hypotheses and proof scripts in the theory format of the proof assistant Isabelle. Then, in many cases, Isabelle can automatically execute these proof scripts and thereby verify the soundness of Ecce's verification process and of the correspondence between program specialisation and inductive theorem proving
Isabelle Béné
No full textBéné Isabelle. Isabelle Béné. In: Diplômées, n°278-279, 2021. 100 ans de parcours. pp. 254-264
Letter and picture from Sarah Isabelle, Buena Vista, Colorado, to James, February 11, 1912
No full textA thank you note written by Sarah Isabelle of Buena Vista, Colorado, to James for Christmas presents and birthday wishes. She also mentions her new role tending the chickens on the farm and enclosed a picture of her feeding the chickens
larsrh/isabelle-cakeml: Isabelle/CakeML v1.0
No full text<p>CakeML is a functional programming language with a proven-correct compiler and runtime system. This entry contains an unofficial version of the CakeML semantics that has been exported from the Lem specifications to Isabelle. Additionally, there are some hand-written theory files that adapt the exported code to Isabelle and port proofs from the HOL4 formalization, e.g. termination and equivalence proofs.</p>
<p>Based on <a href="https://github.com/CakeML/cakeml/releases/tag/v2.0">v2.0</a> of CakeML.</p>
<p>This is the version that has been initially submitted to the <a href="https://devel.isa-afp.org/entries/CakeML.html">Archive of Formal Proofs</a>.</p>
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