Variations on a Theme: A Bibliography on Approaches to Theorem Proving Inspired From Satchmo

This articles is a structured bibliography on theorem provers, approaches to theorem proving, and theorem proving applications inspired from Satchmo, the model generation theorem prover developed in the mid 80es of the 20th century at ECRC, the European Computer- Industry Research Centre. Note that the bibliography given in this article is not exhaustive

A structured argumentation framework for detaching conditional obligations

We present a general formal argumentation system for dealing with the detachment of conditional obligations. Given a set of facts, constraints, and conditional obligations, we answer the question whether an unconditional obligation is detachable by considering reasons for and against its detachment. For the evaluation of arguments in favor of detaching obligations we use a Dung-style argumentation-theoretical semantics. We illustrate the modularity of the general framework by considering some extensions, and we compare the framework to some related approaches from the literature.Comment: This is our submission to DEON 2016, including the technical appendi

Explaining post-apartheid South African human rights foreign policy: unsettled identity and conflicting interests

The end of apartheid in 1994 brought with it many expectations – both domestically and internationally – about the kind of state the new South Africa would be and the foreign policies it would pursue, with many expecting South Africa to pursue a human rights-based foreign policy. However, South Africa has pursued a much more paradoxical foreign policy, with significant gaps between its stated commitment to human rights principles and its action in support of those principles. This article seeks to explain these gaps. Delving into the literature on norms-based and interest-based explanations of state behavior, it argues that both approaches help to explain South Africa’s foreign policy actions. However, it is the unsettled nature of its identities and interests after 1994, as its leaders (in particular Thabo Mbeki) sought to reconcile a commitment to democracy and human rights with equally strong (if not greater) commitments to Afrocentrism and anti-imperialism, which provides the most interesting avenues for exploration

The European Union, borders and conflict transformation: the case of Cyprus

Much of the existing literature on the European Union (EU), conflict transformation and border dynamics has been premised on the assumption that the nature of the border determines EU intervention and the consequences that flow from this in terms of EU impact. The article aims to transcend this literature through assessing how domestic interpretations influence EU border transformation in conflict situations, taking Cyprus as a case study. Moreover, the objective is to fuse the literature on EU bordering impact and perceptions of the EU’s normative projection in conflict resolution. Pursuing this line of inquiry is an attempt to depart from the notion of borders being constructed solely by unidirectional EU logics of engagement or bordering practices to a conceptualization of the border as co-constituted space, where the interpretations of the EU’s normative projections by conflict parties, and the strategies that they pursue, can determine the relative openness of the EU border

Concept logics

Concept languages (as used in BACK, KL-ONE, KRYPTON, LOOM) are employed as knowledge representation formalisms in Artificial Intelligence. Their main purpose is to represent the generic concepts and the taxonomical hierarchies of the domain to be modeled. This paper addresses the combination of the fast taxonomical reasoning algorithms (e.g. subsumption, the classifier etc.) that come with these languages and reasoning in first order predicate logic. The interface between these two different modes of reasoning is accomplished by a new rule of inference, called constrained resolution. Correctness, completeness as well as the decidability of the constraints (in a restricted constraint language) are shown

On abduction and answer generation through constrained resolution

Recently, extensions of constrained logic programming and constrained resolution for theorem proving have been introduced, that consider constraints, which are interpreted under an open world assumption. We discuss relationships between applications of these approaches for query answering in knowledge base systems on the one hand and abduction-based hypothetical reasoning on the other hand. We show both that constrained resolution can be used as an operationalization of (some limited form of) abduction and that abduction is the logical status of an answer generation process through constrained resolution, ie., it is an abductive but not a deductive form of reasoning

A resolution principle for clauses with constraints

We introduce a general scheme for handling clauses whose variables are constrained by an underlying constraint theory. In general, constraints can be seen as quantifier restrictions as they filter out the values that can be assigned to the variables of a clause (or an arbitrary formulae with restricted universal or existential quantifier) in any of the models of the constraint theory. We present a resolution principle for clauses with constraints, where unification is replaced by testing constraints for satisfiability over the constraint theory. We show that this constrained resolution is sound and complete in that a set of clauses with constraints is unsatisfiable over the constraint theory if we can deduce a constrained empty clause for each model of the constraint theory, such that the empty clauses constraint is satisfiable in that model. We show also that we cannot require a better result in general, but we discuss certain tractable cases, where we need at most finitely many such empty clauses or even better only one of them as it is known in classical resolution, sorted resolution or resolution with theory unification

The New International Tax Diplomacy

International tax avoidance by multinational corporations is now frontpage news. At its core, the issue is simple: the tax regimes of different countries allow multinational corporations to book much of their income in low-tax or no-tax jurisdictions, and many of their expenses in high-tax jurisdictions, thereby significantly reducing their tax liabilities. In a time of public austerity, citizens and legislators around the world have been more focused on the resulting erosion of the corporate income tax base than ever before. In response, in 2012, the G-20—the gathering of the leaders of the world’s twenty largest economies—launched the Base Erosion and Profit Shifting (BEPS) project, the most extensive attempt to change international tax norms since the 1920s. In the course of the BEPS project, the field of international tax has adopted the institutional and procedural architecture for multilateral action used in international financial law. This Article is the first to ask whether that architecture will work in the international tax context. To answer that question, this Article first applies lessons from the international financial law literature to assess international tax agreements that are now being reached through soft-law instruments and procedures comparable to those that characterize international financial law. This initial analysis, which draws from the experience in international financial law, is largely pessimistic. However, this Article then describes how model tax treaty law—although also a form of soft law—is highly effective, and differentiates the political economy of international tax law from that of international financial law. As a result, a key theoretical point emerges: bifurcating analysis of multilateral efforts to change international tax norms into their Model Treaty-based and non-Model Treaty-based components is necessary in order to understand the new regime for international tax governance. At a more practical level, bifurcating the analysis highlights that observers should expect the Model Treaty-based parts of the BEPS project to be implemented, as well as most parts of the project focused on tax transparency. By contrast, sustained international coordination in implementing other dimensions of the project is doubtful. In reaching these conclusions, the Article contributes to the broader international economic governance literature by using a high-profile example from international tax diplomacy to show how underlying legal institutions affect the prospects for implementation of international regulatory agreements

Proving theorems by program transformation

In this paper we present an overview of the unfold/fold proof method, a method for proving theorems about programs, based on program transformation. As a metalanguage for specifying programs and program properties we adopt constraint logic programming (CLP), and we present a set of transformation rules (including the familiar unfolding and folding rules) which preserve the semantics of CLP programs. Then, we show how program transformation strategies can be used, similarly to theorem proving tactics, for guiding the application of the transformation rules and inferring the properties to be proved. We work out three examples: (i) the proof of predicate equivalences, applied to the verification of equality between CCS processes, (ii) the proof of first order formulas via an extension of the quantifier elimination method, and (iii) the proof of temporal properties of infinite state concurrent systems, by using a transformation strategy that performs program specialization