Combination of convex theories: Modularity, deduction completeness, and explanation

AbstractDecision procedures are key components of theorem provers and constraint satisfaction systems. Their modular combination is of prime interest for building efficient systems, but their effective use is often limited by poor interface capabilities, when such procedures only provide a simple “sat/unsat” answer. In this paper, we develop a framework to design cooperation schemas between such procedures while maintaining modularity of their interfaces. First, we use the framework to specify and prove the correctness of classic combination schemas by Nelson–Oppen and Shostak. Second, we introduce the concept of deduction complete satisfiability procedures, we show how to build them for large classes of theories, then we provide a schema to modularly combine them. Third, we consider the problem of modularly constructing explanations for combinations by re-using available proof-producing procedures for the component theories

Contract Based Verification of IEC 61499

14th International Conference on Industrial Informatics (INDIN 2016). 18 to 21, Jul, 2016, Factory Automation. Poitiers, France.The IEC 61499 standard proposes an event driven execution model for component based (in terms of Function Blocks), distributed industrial automation applications. However, the standard provides only an informal execution semantics, thusin consequence behavior and correctness relies on the design decisions made by the tool vendor. In this paper we present the formalization of a subset of the IEC 61499 standard in order to provide an underpinning for the static verification of Function Block models by means of deductive reasoning. Specifically, we contribute by addressing verification at the component,algorithm, and ECC levels. From Function Block descriptions, enrichedwith formal contracts, we show that correctness of component compositions, as well as functional and transitional behavior can be ensured. Feasibility of the approach is demonstrated by manually encoding a set of representative use-cases in WhyML,for which the verification conditions are automatically derived (through the Why3 platform) and discharged (using automaticSMT-based solvers). Furthermore, we discuss opportunities and challenges towards deriving certified executables for IEC 61499 models.info:eu-repo/semantics/publishedVersio

Proceedings of the Second NASA Formal Methods Symposium

This publication contains the proceedings of the Second NASA Formal Methods Symposium sponsored by the National Aeronautics and Space Administration and held in Washington D.C. April 13-15, 2010. Topics covered include: Decision Engines for Software Analysis using Satisfiability Modulo Theories Solvers; Verification and Validation of Flight-Critical Systems; Formal Methods at Intel -- An Overview; Automatic Review of Abstract State Machines by Meta Property Verification; Hardware-independent Proofs of Numerical Programs; Slice-based Formal Specification Measures -- Mapping Coupling and Cohesion Measures to Formal Z; How Formal Methods Impels Discovery: A Short History of an Air Traffic Management Project; A Machine-Checked Proof of A State-Space Construction Algorithm; Automated Assume-Guarantee Reasoning for Omega-Regular Systems and Specifications; Modeling Regular Replacement for String Constraint Solving; Using Integer Clocks to Verify the Timing-Sync Sensor Network Protocol; Can Regulatory Bodies Expect Efficient Help from Formal Methods?; Synthesis of Greedy Algorithms Using Dominance Relations; A New Method for Incremental Testing of Finite State Machines; Verification of Faulty Message Passing Systems with Continuous State Space in PVS; Phase Two Feasibility Study for Software Safety Requirements Analysis Using Model Checking; A Prototype Embedding of Bluespec System Verilog in the PVS Theorem Prover; SimCheck: An Expressive Type System for Simulink; Coverage Metrics for Requirements-Based Testing: Evaluation of Effectiveness; Software Model Checking of ARINC-653 Flight Code with MCP; Evaluation of a Guideline by Formal Modelling of Cruise Control System in Event-B; Formal Verification of Large Software Systems; Symbolic Computation of Strongly Connected Components Using Saturation; Towards the Formal Verification of a Distributed Real-Time Automotive System; Slicing AADL Specifications for Model Checking; Model Checking with Edge-valued Decision Diagrams; and Data-flow based Model Analysis

Building Extended Canonizers by Graph-Based Deduction

We consider the problem of efficiently building extended canonizers, which are capable of solving the uniform word problem for some first-order theories. These reasoning artifacts have been introduced in previous work to solve the lack of modularity of Shostak combination schema while retaining its efficiency. It is known that extended canonizers can be modularly combined to solve the uniform word problem in unions of theories. Unfortunately, little is known about efficiently implementing such canonizers for component theories, especially those of interest for verification like, e.g., those of uninterpreted function symbols or lists. In this paper, we investigate this problem by adapting and combining work on rewriting-based decision procedures for satisfiability in first-order theories and SER graphs, a graph-based method defined for abstract congruence closure. Our goal is to build graph-based extended canonizers for theories which are relevant for verification. Based on graphs our approach addresses implementation issues that were lacking in previous rewriting-based decision procedure approaches and which are important to argue the viability of extended canonizers

Romanticism and Women Poets: Opening the Doors of Reception

One of the most exciting developments in Romantic studies in the past decade has been the rediscovery and repositioning of women poets as vital and influential members of the Romantic literary community. This is the first volume to focus on women poets of this era and to consider how their historical reception challenges current conceptions of Romanticism. With a broad, revisionist view, the essays examine the poetry these women produced, what the poets thought about themselves and their place in the contemporary literary scene, and what the recovery of their works says about current and past theoretical frameworks. The contributors focus their attention on such poets as Felicia Hemans, Letitia Elizabeth Landon, Charlotte Smith, Anna Barbauld, Mary Lamb, and Fanny Kemble and argue for a significant rethinking of Romanticism as an intellectual and cultural phenomenon. Grounding their consideration of the poets in cultural, social, intellectual, and aesthetic concerns, the authors contest the received wisdom about Romantic poetry, its authors, its themes, and its audiences. Some of the essays examine the ways in which many of the poets sought to establish stable positions and identities for themselves, while others address the changing nature over time of the reputations of these women poets. Harriet Kramer Linkin, associate professor of English at New Mexico State University, is coeditor of Approaches to Teaching British Women Poets of the Romantic Period. Stephen C. Behrendt, George Holmes Distinguished Professor of English at the University of Nebraska, is author of Royal Mourning and Regency Culture. This volume takes an important step toward redefining the literary mainstream of the Romantic period. —Choice Discloses a much more populous Romantic period that we have yet been accustomed to study and teach. . . . This impressively coherent collection of essays presents a united front in arguing for a long-needed expansion of the Romantic canon, recognizing women\u27s valuable contributions to its most popular poetic genres. —Eighteenth-Century Women Those teaching women poets of the Romantic period must address a number of questions: What was the initial reception of these poets? Why did they fade from public consciousness? What circumstances have led to renewed interest in these writers today? This volume will help us address these issues subtly and creatively. —Elizabeth Kraft, University of Georgia Offers a range of positions and methods that challenge many of the major currents in scholarship on romantic women writers. These challenges are fresh, exciting, and absolutely necessary if the study of women writers in the romantic period is to have a vital intellectual future. —Mary Favret, Indiana University Absolutely must be read. —Romanticism on the Net An excellent collection. —Studies in English Literature, 1500-1900 This valuable and wide-ranging collection will provide the reader with ample material for further investigation. —Times Literary Supplementhttps://uknowledge.uky.edu/upk_english_language_and_literature_british_isles/1064/thumbnail.jp