1,721,259 research outputs found
A natural deduction calculus for gödel-dummett logic internalizing proof-search control mechanisms?
No full textWe introduce a natural deduction calculus for the Gödel- Dummett Logic LC semantically characterized by linearly ordered Kripke models. Our calculus is inspired by an analogous calculus for Intuitionistic logic (IPL) internalizing mechanisms to reduce the proof-search space that has been used to define a goal-oriented proof-search procedure for IPL. In this paper we present the calculus for LC and we sketch its soundness and completeness
A forward internal calculus for model generation in S4
No full textWe propose an internal calculus to check the satisfiability of a set of formulas in . Our calculus directly supports model extraction and is designed so to implement a forward proof-search strategy that can be understood as a top-down construction of a model. We prove that the extracted models have minimal height
Forward refutation for Gödel-Dummett Logics
Full text linkWe propose a refutation calculus to check the unprovability of a formula in Gödel-Dummett logics. From refutations we can directly extract countermodels for unprovable formulas, moreover the calculus is designed so to support a forward proof-search strategy that can be understood as a top-down construction of a model
A New Approach to Clausification for Intuitionistic Propositional Logic
Full text linkIn recent years some papers have addressed the problem of the validity in Intuitionistic Propositional Logic and in some intermediate propositional logics using the approach proposed by Claessen and Rosén of reduction to Satisfiability Modulo Theories (SMT). This approach depends on an initial pre-processing phase that reduces the input formula in the intuitionistic language to an equivalent sequent in the language of clauses. In this work we present an extension of the clauses used by Claessen and Rosén that allows us to define a natural relationship between the semantics of the extended clauses and Kripke semantics. As an application, we show how Answer Set Programming can be used to check the intuitionistic validity of a formula and to generate Kripke countermodels for countersatisfiable formulas
SAT-based proof search in intermediate propositional logics
Full text linkWe present a decision procedure for intermediate logics relying on a modular extension of the SAT-based prover intuitR for IPL (Intuitionistic Propositional Logic). Given an intermediate logic L and a formula α, the procedure outputs either a Kripke countermodel for α or the instances of the characteristic axioms of L that must be added to IPL in order to prove α. The procedure exploits an incremental SAT-solver; during the computation, new clauses are learned and added to the solver
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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