Towards Static Analysis of Functional Programs using Tree Automata Completion

This paper presents the first step of a wider research effort to apply tree automata completion to the static analysis of functional programs. Tree Automata Completion is a family of techniques for computing or approximating the set of terms reachable by a rewriting relation. The completion algorithm we focus on is parameterized by a set E of equations controlling the precision of the approximation and influencing its termination. For completion to be used as a static analysis, the first step is to guarantee its termination. In this work, we thus give a sufficient condition on E and T(F) for completion algorithm to always terminate. In the particular setting of functional programs, this condition can be relaxed into a condition on E and T(C) (terms built on the set of constructors) that is closer to what is done in the field of static analysis, where abstractions are performed on data.Comment: Proceedings of WRLA'14. 201

Termination by completion

Projet EURECAThis paper presents a completion procedure for proving termination of term rewrite systems. It works as follows. Given a term rewrite system R supposed to terminate and a term rewrite system T used to transform R, the completion builds an auxiliary term rewrite system S, the system transformed of R by T. The termination of S and T associated with a property called local cooperation implies the termination of R. If the process terminates this provides a mechanical proof of the termination of R

Contractual allocation of decision rights and incentives: The case of automobile distribution

We analyze empirically the allocation of rights and monetary incentives in automobile franchise contracts. These contracts substantially restrict the decision rights of dealers and grant manufacturers extensive contractual completion and enforcement powers, converting the manufacturers, de facto, in a sort of quasi-judiciary instance. Variation in the allocation of decision rights and incentive intensity is explained by the incidence of moral hazard in the relation. In particular, when the cost of dealer moral hazard is higher and the risk of manufacturer opportunism is lower, manufacturers enjoy more discretion in determining the performance required from their dealers and in using mechanisms such as monitoring, termination and monetary incentives to ensure such performance is provided. We also explore the existence of interdependencies between the different elements of the system. and find some complementarities between completion and termination rights, and between monitoring rights and the intensity of incentives.Franchising, contracts, self-enforcement, incentives, complementarities, automobiles

A Reduction-Preserving Completion for Proving Confluence of Non-Terminating Term Rewriting Systems

We give a method to prove confluence of term rewriting systems that contain non-terminating rewrite rules such as commutativity and associativity. Usually, confluence of term rewriting systems containing such rules is proved by treating them as equational term rewriting systems and considering E-critical pairs and/or termination modulo E. In contrast, our method is based solely on usual critical pairs and it also (partially) works even if the system is not terminating modulo E. We first present confluence criteria for term rewriting systems whose rewrite rules can be partitioned into a terminating part and a possibly non-terminating part. We then give a reduction-preserving completion procedure so that the applicability of the criteria is enhanced. In contrast to the well-known Knuth-Bendix completion procedure which preserves the equivalence relation of the system, our completion procedure preserves the reduction relation of the system, by which confluence of the original system is inferred from that of the completed system

Knuth-Bendix Completion with Modern Termination Checking, Master\u27s Thesis, August 2006

Knuth-Bendix completion is a technique for equational automated theorem proving based on term rewriting. This classic procedure is parametrized by an equational theory and a (well-founded) reduction order used at runtime to ensure termination of intermediate rewriting systems. Any reduction order can be used in principle, but modern completion tools typically implement only a few classes of such orders (e.g., recursive path orders and polynomial orders). Consequently, the theories for which completion can possibly succeed are limited to those compatible with an instance of an implemented class of orders. Finding and specifying a compatible order, even among a small number of classes, is challenging in practice and crucial to the success of the method. In this thesis, a new variant on the Knuth-Bendix completion procedure is developed in which no order is provided by the user. Modern termination-checking methods are instead used to verify termination of rewriting systems. We prove the new method correct and also present an implementation called Slothrop which obtains solutions for theories that do not admit typical orders and that have not previously been solved by a fully automatic tool

The notion of completion in Modern Greek: An analysis of aspectively adversative sentences

Wydział NeofilologiiTematem niniejszej dysertacji jest koncepcja dokonaności oraz sposoby jej językowego wyrażania w języku nowogreckim (współczesnym języku greckim). W pracy przebadano zdania aspektywnie adwersatywne a na podstawie otrzymanych wyników zaproponowano szereg postulatów opisujących fragment nowogreckiej rzeczywistości aspektywnej. Otrzymana teoria została następnie zweryfikowana przy pomocy dedukcyjnego modelu wyjaśniający Hempla i Openheima (1948). Praca jest pierwszą na gruncie językoznawstwa nowogreckiego wykorzystującą metodę postulatywną i dedukcyjny model wyjaśniający w odniesieniu do kategorii aspektu. W pracy poczyniono m.in. następujące założenia: 1) dokonaność jest znaczeniem złożonym łączącym w sposób obligatoryjny znaczenie terminacji i holiczności (całościowości), 2) w języku nowogreckim znaczenie terminacji może być niesione leksykalnie lub semicznie a znaczenie holiczności wyłącznie leksykalnie, 3) czasowniki momentalne leksyfikują jednocześnie terminację i holiczność. W oparciu o powyższe założenia wyodrębniono trzy grupy nowogreckich form czasownikowych: 1) autosygnifikatorów dokonaności, czyli wystarczających wykładników tego znaczenia, 2) kosygnifikatorów dokonaności, które niosą znaczenie dokonaności wspólnie z leksyfikatorem holiczności oraz 3) leksyfikatorów dokonaności, które wyrażają obligatoryjnie dokonaność podzdarzeń, lecz niekoniecznie całego zdarzenia.The present dissertation concerns the notion of completion and how it is lingually expressed in Modern Greek. Within the framework of the research, aspectively adversative sentences were analysed. Based on the results, a set of postulates describing the Modern Greek aspective reality was proposed. Then, Hampel and Oppenheim’s (1948) deductive model of explanation has been employed, in order to verify the adequacy of the proposed theory. It is the first work in Modern Greek aspectology that employs the postulational method and the deductive model of explanation. Among the assumptions made in the dissertation are: 1) completion is a complex meaning involving obligatorily the meaning of termination and holicity (the property of being whole), 2) in Modern Greek the meaning of termination may be lexified (conveyed by lexical morphs) or semified (conveyed by affixes) whereas the meaning of holicity may be solely lexified, and 3) forms of momentary verbs lexify simultaneously termination and holicity. In the light of the above assumptions, the following three groups of Modern Greek verb forms were distinguished: 1) autosignificators of completion, that is sufficient significators (markers) of completion, 2) cosignificators of completion, which convey completion jointly with lexificators of holicity, and 3) lexificators of completion, which refer to events composed of completed subevents

Essays on the Impact of Antitrust Regulation on Corporate Mergers and Divestitures

A merger requires at least one of two separate yet equally important sets of negotiations. The first involves merging parties to discuss issues related to the terms of the merger, including target firm\u27s valuation. The second resolves disputes between the merging parties and the government regulatory agency over the potential anticompetitive impact of the merger. In the first essay, I investigate the probability of completing an acquisition deal conditional on the government approval by applying a nested logit model. My results support the findings of Eckbo (1985), Coate, Higgins, and McChesney (1990), and Coate (2005) that mergers that are expected to increase market concentration are more likely to be challenged by the government. Consistent with Officer (2003) and Bates and Lemmon (2003), I find that including target termination fees is significantly positively related to the probability of completion irrespective of whether the deal is challenged or not. However, I document that including target termination fees deters competitive bidding only if the deal was challenged and leads to higher bid premium to the target firm only if the deal was not challenged. Conditional on not being challenged, acquirer\u27s investment opportunities and the relative size of acquirer and target firms are significantly positively related to the probability of completion, while target investment opportunities and the existence of multiple bidders are significantly negatively related to the probability of completion. Conditional on the merger being challenged, acquirer\u27s investment opportunities and the existence of target termination fees are positively related to the probability of completion and only the existence of multiple bidders is negatively related to the probability of completion. In the second essay, I study the impact of asset sales on the firm\u27s focus level, information asymmetry, and operating performance. I find that following a merger facilitating asset sale the firm becomes more diversified, its information asymmetry increases, and its operating performance does not change while following a non merger related asset sale, the firm becomes more focused, its information asymmetry decreases, and its operating performance improves significantly

The Certification Problem Format

We provide an overview of CPF, the certification problem format, and explain some design decisions. Whereas CPF was originally invented to combine three different formats for termination proofs into a single one, in the meanwhile proofs for several other properties of term rewrite systems are also expressible: like confluence, complexity, and completion. As a consequence, the format is already supported by several tools and certifiers. Its acceptance is also demonstrated in international competitions: the certified tracks of both the termination and the confluence competition utilized CPF as exchange format between automated tools and trusted certifiers.Comment: In Proceedings UITP 2014, arXiv:1410.785

Predictors of Early Termination of Pediatric Oncology Clinical Trials Due to Poor Accrual: An Exploratory Analysis

Purpose: The purpose of this dissertation is to explore factors affecting accrual and completion of pediatric oncology clinical trials. This dissertation includes a scoping review of barriers and facilitators to enrollment in pediatric oncology clinical trials, a systematic review of trial-level factors affecting accrual and completion of oncology clinical trials, and an exploratory analysis of trial-level factors affecting accrual and completion of pediatric oncology clinical trials from ClinicalTrials.gov data. Problem/Aims: Cancer is the second leading cause of death in children. Clinical trials explore potential new therapies for children with cancer by determining safety and effectiveness of interventions. The literature demonstrates widespread inadequate accrual of trial participants and associated early termination of oncology clinical trials. This dissertation aimed to provide evidence of trial-level factors affecting accrual and completion of pediatric oncology clinical trials by reviewing the literature, identifying possible trial-level factors, and performing an exploratory analysis of the ClinicalTrials.gov dataset. Design including theoretical basis: A modified version of the Social Ecological Model and Arskey and O’Malley’s framework guided the scoping review. Bennette et al.’s framework, along with that of Knafl and Whittmore, directed the systematic review. Bennette et al.’s framework also guided the exploratory analysis using the ClinicalTrials.gov dataset. Findings: Barriers to enrollment in pediatric oncology clinical trials exist at the trial, individual, interpersonal and organizational levels. Several trial-level barriers to enrollment in adult oncology clinical trials previously were identified, such as enrollment, intervention type, phase, allocation, arm type, sponsor, number of participating facilities, and primary disease. The exploratory analysis indicated none of the aforementioned variables and others such as primary purpose, number of primary outcomes, interventional study model, and number of arms were predictive of early termination of pediatric oncology trials due to low accrual. However, odds for studies to terminate early were 4.7 times higher for those that used a data and safety monitoring committee compared to those that did not (p = 0.05). Conclusion: Findings from the scoping and systematic reviews suggest there are trial-level factors that affect early termination of pediatric oncology trials due to low accrual. Findings from the exploratory study indicated that use of a data and safety monitoring committee plays an important role in early trial termination due to low accrual. The design of future pediatric oncology clinical trials should incorporate approaches to minimize trial-level factors that are associated with or predictive of early trial termination. Additional studies examining trial-level factors should utilize multiple trial databases and investigate pediatric oncology trials that have been conducted worldwide

COLUMBIA MEDICAL CENTER AND THE COCAINE ADDICTED PHARMACIST (A)

Tom Zenor, a pharmacist for Columbia Medical Center, became addicted to cocaine. He checked himself into a rehabilitation center and, upon request, was placed on leave as allowed by the Family Medical Leave Act (FMLA). During his FMLA leave the company decided to terminate his employment upon the completion of his twelve week leave of absence. Columbia, in an attempt to be proactive, is considering any legal recourse Zenor might attempt. Columbia’s Human Resources manager, Carmen Estrada, is preparing evidence to defend the company against a potential Americans with Disabilities Act (ADA) lawsuit. Her primary concern is that Zenor will claim that his cocaine addiction is a qualified disability under the ADA. (Contact author for a copy of the complete report.)Personnel, Unjust Termination, At-Will Employment