81 research outputs found

    A rigorous treatment of Meek's method for single transferable vote with formal proofs of key properties

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    This thesis presents a mechanised formalisation of key concepts and properties of Meek's method of Single Transferable Vote (STV). This method is currently in use in a number of local elections in New Zealand, the Royal Statistical Society, and even the Stack Exchange network. Using a formal approach, we show that the iterative solution to the surplus transfer round of Meek's method converges to a unique and valid solution, and connect a functional implementation of its key components to a more abstract and generalised proof. Along the way, we consider and address issues present in existing pen-and-paper proofs, and discuss a general representation of strict ballots suitable for the proof patterns encountered in our formal development and for the implementation of Meek's method. We believe that this work pushes the boundaries of interactive theorem proving for the formal verification of voting algorithms, and offers multiple promising avenues for further work on formally verifying the correctness and termination of STV methods in Isabelle/HOL

    A Human-on-the-Loop Optimization Autoformalism Approach for Sustainability

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    This paper outlines a natural conversational approach to solving personalized energy-related problems using large language models (LLMs). We focus on customizable optimization problems that necessitate repeated solving with slight variations in modeling and are user-specific, hence posing a challenge to devising a one-size-fits-all model. We put forward a strategy that augments an LLM with an optimization solver, enhancing its proficiency in understanding and responding to user specifications and preferences while providing nonlinear reasoning capabilities. Our approach pioneers the novel concept of human-guided optimization autoformalism, translating a natural language task specification automatically into an optimization instance. This enables LLMs to analyze, explain, and tackle a variety of instance-specific energy-related problems, pushing beyond the limits of current prompt-based techniques. Our research encompasses various commonplace tasks in the energy sector, from electric vehicle charging and Heating, Ventilation, and Air Conditioning (HVAC) control to long-term planning problems such as cost-benefit evaluations for installing rooftop solar photovoltaics (PVs) or heat pumps. This pilot study marks an essential stride towards the context-based formulation of optimization using LLMs, with the potential to democratize optimization processes. As a result, stakeholders are empowered to optimize their energy consumption, promoting sustainable energy practices customized to personal needs and preferences

    LLMSTEP: LLM proofstep suggestions in Lean

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    We present LLMSTEP, a tool for integrating a language model into the Lean proof assistant. LLMSTEP is a Lean 4 tactic that sends a user's proof state to a server hosting a language model. The language model generates suggestions, which are checked in Lean and displayed to a user in their development environment. We provide a baseline language model, along with code for fine-tuning and evaluation to support further development. We provide server implementations that run on CPU, a CUDA GPU, or a Google Colab notebook, as a step towards fast, effective language model suggestions for any user

    Choreographies and Cost Semantics for Reliable Communicating Systems

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    Communicating systems have become ubiquitous in today\u27s society.Unfortunately, the complexity of their interactions makesthem particularly prone to failures such as deadlocked statescaused by misbehaving components, or memory exhaustion due to a surgein message traffic (malicious or not).These vulnerabilities constitute a real risk to users, withconsequences ranging from minor inconveniences to the possibility ofloss of life and capital.This thesis presents results that aim to increase the reliability of communicating systems.First, we implement a choreography language that can, by construction, only describe deadlock-free systems.Second, we develop a cost semantics to prove programs free of out-of-memory errors.Lastly, we improve both results by using novel semantic approaches that strengthen key theorems and facilitate further proof development.All of these results are formalized in the HOL4 theorem prover and integrated with the CakeML verified stack

    Type Theory as a Language Workbench

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    Language Workbenches offer language designers an expressive environment in which to create their Domain Specific Languages (DSLs). Similarly, research into mechanised meta-theory has shown how dependently typed languages provide expressive environments to formalise and study DSLs and their meta-theoretical properties. But can we claim that dependently typed languages qualify as language workbenches? We argue yes! We have developed an exemplar DSL called VĂ©lo that showcases not only dependently typed techniques to realise and manipulate Intermediate Representations (IRs), but that dependently typed languages make fine language workbenches. VĂ©lo is a simple verified language with well-typed holes and comes with a complete compiler pipeline: parser, elaborator, REPL, evaluator, and compiler passes. Specifically, we describe our design choices for well-typed IR design that includes support for well-typed holes, how CSE is achieved in a well-typed setting, and how the mechanised type-soundness proof for VĂ©lo is the source of the evaluator

    Teaching Intuitionistic and Classical Propositional Logic Using Isabelle

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    We describe a natural deduction formalization of intuitionistic and classical propositional logic in the Isabelle/Pure framework. In contrast to earlier work, where we explored the pedagogical benefits of using a deep embedding approach to logical modelling, here we employ a logical framework modelling. This gives rise to simple and natural teaching examples and we report on the role it played in teaching our Automated Reasoning course in 2020 and 2021.Comment: In Proceedings ThEdu'21, arXiv:2202.0214

    33Úmes Journées Francophones des Langages Applicatifs

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    International audienceLes 33Ăšmes JournĂ©es Francophones des Langages Applicatifs (JFLA) se sont tenues Ă  Saint-MĂ©dard-d'Excideuil, plus prĂ©cisĂ©ment Domaine d'EssendiĂ©ras (PĂ©rigord), du mardi 28 juin 2022 au vendredi 1er juillet 2022.Les JFLA rĂ©unissent concepteurs, utilisateurs et thĂ©oriciens ; elles ont pour ambition de couvrir les domaines des langages applicatifs, de la preuve formelle, de la vĂ©rification de programmes, et des objets mathĂ©matiques qui sous-tendent ces outils. Ces domaines doivent ĂȘtre pris au sens large : nous souhaitons promouvoir les ponts entre les diffĂ©rentes thĂ©matiques.- Langages fonctionnels et applicatifs : sĂ©mantique, compilation, optimisation, typage, mesures, extensions par d'autres paradigmes.- Assistants de preuve : implĂ©mentation, nouvelles tactiques, dĂ©veloppements prĂ©sentant un intĂ©rĂȘt technique ou mĂ©thodologique.- Logique, correspondance de Curry-Howard, rĂ©alisabilitĂ©, extraction de programmes, modĂšles.- SpĂ©cification, prototypage, dĂ©veloppements formels d'algorithmes.- VĂ©rification de programmes ou de modĂšles, mĂ©thode dĂ©ductive, interprĂ©tation abstraite, raffinement.- Utilisation industrielle des langages fonctionnels et applicatifs, ou des mĂ©thodes issues des preuves formelles, outils pour le web.Les articles soumis aux JFLA sont relus par au moins deux personnes s'ils sont acceptĂ©s, trois personnes s'ils sont rejetĂ©s. Les critiques des relecteurs sont toujours bienveillantes et la plupart du temps encourageantes et constructives, mĂȘme en cas de rejet

    Proceedings of the 22nd Conference on Formal Methods in Computer-Aided Design – FMCAD 2022

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    The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing

    Automated Reasoning

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    This volume, LNAI 13385, constitutes the refereed proceedings of the 11th International Joint Conference on Automated Reasoning, IJCAR 2022, held in Haifa, Israel, in August 2022. The 32 full research papers and 9 short papers presented together with two invited talks were carefully reviewed and selected from 85 submissions. The papers focus on the following topics: Satisfiability, SMT Solving,Arithmetic; Calculi and Orderings; Knowledge Representation and Jutsification; Choices, Invariance, Substitutions and Formalization; Modal Logics; Proofs System and Proofs Search; Evolution, Termination and Decision Prolems. This is an open access book

    Programming Languages and Systems

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    This open access book constitutes the proceedings of the 31st European Symposium on Programming, ESOP 2022, which was held during April 5-7, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 21 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. They deal with fundamental issues in the specification, design, analysis, and implementation of programming languages and systems
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