Automated Verification of Practical Garbage Collectors

Garbage collectors are notoriously hard to verify, due to their low-level interaction with the underlying system and the general difficulty in reasoning about reachability in graphs. Several papers have presented verified collectors, but either the proofs were hand-written or the collectors were too simplistic to use on practical applications. In this work, we present two mechanically verified garbage collectors, both practical enough to use for real-world C# benchmarks. The collectors and their associated allocators consist of x86 assembly language instructions and macro instructions, annotated with preconditions, postconditions, invariants, and assertions. We used the Boogie verification generator and the Z3 automated theorem prover to verify this assembly language code mechanically. We provide measurements comparing the performance of the verified collector with that of the standard Bartok collectors on off-the-shelf C# benchmarks, demonstrating their competitiveness

Investigation, Development, and Evaluation of Performance Proving for Fault-tolerant Computers

A number of methodologies for verifying systems and computer based tools that assist users in verifying their systems were developed. These tools were applied to verify in part the SIFT ultrareliable aircraft computer. Topics covered included: STP theorem prover; design verification of SIFT; high level language code verification; assembly language level verification; numerical algorithm verification; verification of flight control programs; and verification of hardware logic

The role of umbrella agreements in achieving sustainability goals : energy efficiency at the Empire State building

In this paper we investigate whether innovative and flexible contractual arrangements can support the process of achieving ambitious sustainability goals. We explore this question through an analysis of the role of umbrella agreements in driving energy savings in the building sector. Drawing on a case study of the iconic Empire State building, we examine the typical challenges faced by clients and contractors in devising suitable agreements that facilitate managing contractual and performance risks, as well as the sharing of responsibilities and cooperation between multiple project stakeholders. We find that the project arrangements appear to exhibit the adoption of the key characteristics commonly found in umbrella agreements which incorporate sustainability measures that maximize income through efficient delivery of outcomes. Specifically, this means that they need to enable stakeholders to manage repeated review cycles, complex perceptions and expectations, and different tacit assumptions and codes of behaviour, as well as managing and communicating in networks and obtaining agreement also from non-contractual parties. Moreover, we demonstrate that umbrella agreements can facilitate a network perspective of business relationships by emphasizing value co-creation and the embeddedness of firms within a network of interactions

Emerging trends proceedings of the 17th International Conference on Theorem Proving in Higher Order Logics: TPHOLs 2004

technical reportThis volume constitutes the proceedings of the Emerging Trends track of the 17th International Conference on Theorem Proving in Higher Order Logics (TPHOLs 2004) held September 14-17, 2004 in Park City, Utah, USA. The TPHOLs conference covers all aspects of theorem proving in higher order logics as well as related topics in theorem proving and verification. There were 42 papers submitted to TPHOLs 2004 in the full research cate- gory, each of which was refereed by at least 3 reviewers selected by the program committee. Of these submissions, 21 were accepted for presentation at the con- ference and publication in volume 3223 of Springer?s Lecture Notes in Computer Science series. In keeping with longstanding tradition, TPHOLs 2004 also offered a venue for the presentation of work in progress, where researchers invite discussion by means of a brief introductory talk and then discuss their work at a poster session. The work-in-progress papers are held in this volume, which is published as a 2004 technical report of the School of Computing at the University of Utah

Verification conditions for source-level imperative programs

This paper is a systematic study of verification conditions and their use in the context of program verification. We take Hoare logic as a starting point and study in detail how a verification conditions generator can be obtained from it. The notion of program annotation is essential in this process. Weakest preconditions and the use of updates are also studied as alternative approaches to verification conditions. Our study is carried on in the context of a While language. Important extensions to this language are considered toward the end of the paper. We also briefly survey modern program verification tools and their approaches to the generation of verification conditions.Fundação para a Ciência e a Tecnologia (FCT

Derivation of logic programs

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From Traditional Set Theory – that of Cantor, Hilbert , Gödel, Cohen – to Its Necessary Quantum Extension

The original purpose of the present study, 2011, started with a preprint «On the Probable Failure of the Uncountable Power Set Axiom», 1988, is to save from the transfinite deadlock of higher set theory the jewel of mathematical Continuum — this genuine, even if mostly forgotten today raison d’être of all traditional set-theoretical enterprises to Infinity and beyond, from Georg Cantor to David Hilbert to Kurt Gödel to W. Hugh Woodin to Buzz Lightyear

Topics in arithmetic and determinacy

This thesis is about Arithmetical Determinacy. Loosely, this is the problem of whether every question in arithmetic has a determinate answer. In this work I discuss how to exactly understand the concept of determinacy, I criticise arguments for and against the claim that arithmetic is determinate, and examine how questions about determinacy may be applied to other debates in the philosophy of mathematics. Chapter 1 isolates different ways of understanding the problem of arithmetical determinacy. Chapter 2 turns to mathematical structuralism and explains how popular computability constraints thought to determine the reference of our arithmetical vocabulary are actually unsuccessful in securing determinacy. Chapter 3 criticises an interesting idea for securing determinacy via our experience with supertasks. Chapter 4 explores the phenomenon of mutually inconsistent satisfaction classes and motivates a new account of determinacy in terms of sentences possessing non-classical truth-values. Chapter 5 defends strict finitism, framing some objections against the view in terms of the concept of arithmetical determinacy

On the engineering of crucial software

The various aspects of the conventional software development cycle are examined. This cycle was the basis of the augmented approach contained in the original grant proposal. This cycle was found inadequate for crucial software development, and the justification for this opinion is presented. Several possible enhancements to the conventional software cycle are discussed. Software fault tolerance, a possible enhancement of major importance, is discussed separately. Formal verification using mathematical proof is considered. Automatic programming is a radical alternative to the conventional cycle and is discussed. Recommendations for a comprehensive approach are presented, and various experiments which could be conducted in AIRLAB are described