Hebrew University of Jerusalem
Department of Philosophy
PhD, 1969
Areas of Interest
 Normative Ethics Logic and Philosophy of Logic Philosophy of Mathematics Philosophy of Probability
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##### Cut and pay with Marcelo Finger Journal of Logic, Language and Information 15 (3): 195-218. 2006.
In this paper we study families of resource aware logics that explore resource restriction on rules; in particular, we study the use of controlled cut-rule and introduce three families of parameterised logics that arise from different ways of controlling the use of cut. We start with a formulation of classical logic in which cut is non-eliminable and then impose restrictions on the use of cut. Three Cut-and-Pay families of logics are presented, and it is shown that each family provides an approx…Read more
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##### Combining Temporal Logic Systems with Marcelo Finger Notre Dame Journal of Formal Logic 37 (2): 204-232. 1996.
This paper investigates modular combinations of temporal logic systems. Four combination methods are described and studied with respect to the transfer of logical properties from the component one-dimensional temporal logics to the resulting combined two-dimensional temporal logic. Three basic logical properties are analyzed, namely soundness, completeness, and decidability. Each combination method comprises three submethods that combine the languages, the inference systems, and the semantics of…Read more
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##### Analysis of the Talmudic Argumentum A Fortiori Inference Rule using Matrix Abduction with M. Abraham and U. Schild Studia Logica 92 (3): 281-364. 2009.
We motivate and introduce a new method of abduction, Matrix Abduction, and apply it to modelling the use of non-deductive inferences in the Talmud such as Analogy and the rule of Argumentum A Fortiori. Given a matrix with entries in {0,1}, we allow for one or more blank squares in the matrix, say $a_{i,j} =?.$ The method allows us to decide whether to declare $a_{i,j} = 0$ or $a_{i,j} = 1$ or $a_{i,j} =?$ undecided. This algorithmic method is then applied to modelling several legal and practical…Read more
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##### Two dimensional Standard Deontic Logic [including a detailed analysis of the 1985 Jones–Pörn deontic logic system] with Mathijs de Boer, Xavier Parent, and Marija Slavkovic Synthese 187 (2): 623-660. 2012.
This paper offers a two dimensional variation of Standard Deontic Logic SDL, which we call 2SDL. Using 2SDL we can show that we can overcome many of the difficulties that SDL has in representing linguistic sets of Contrary-to-Duties (known as paradoxes) including the Chisholm, Ross, Good Samaritan and Forrester paradoxes. We note that many dimensional logics have been around since 1947, and so 2SDL could have been presented already in the 1970s. Better late than never! As a detailed case study i…Read more
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##### On Kreisel's notion of validity in post systems Studia Logica 35 (3). 1976.
This paper investigates various interpretations of HPC (Heyting's predicate calculus) and mainly of HPC0 (Heyting's propositional calculus) in Post systems.§1 recalls some background material concerning HPC including the Kripke and Beth interpretations, and later sections study the various interpretations available.
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##### Annotation Theories over Finite Graphs with Andrzej Szałas Studia Logica 93 (2): 147-180. 2009.
In the current paper we consider theories with vocabulary containing a number of binary and unary relation symbols. Binary relation symbols represent labeled edges of a graph and unary relations represent unique annotations of the graph's nodes. Such theories, which we call annotation theories^ can be used in many applications, including the formalization of argumentation, approximate reasoning, semantics of logic programs, graph coloring, etc. We address a number of problems related to annotati…Read more
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##### Parsing natural language using LDS: a prototype with M. Finger, R. Kibble, and R. Kempson Logic Journal of the IGPL 5 (5): 647-671. 1997.
This paper describes a prototype implementation of a Labelled Deduction System for natural language interpretation, where interpretation is taken to be the process of understanding a natural language utterance. The implementation models the process of understanding wh-gap dependencies in questions and relative clauses for a fragment of English. The paper is divided in three main sections. In Section 1, we introduce the basic architecture of the system. Section 2 outlines a prototype implementati…Read more
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##### Goal-Directed Proof Theory Kluwer Academic. 2000.
Goal Directed Proof Theory presents a uniform and coherent methodology for automated deduction in non-classical logics, the relevance of which to computer science is now widely acknowledged. The methodology is based on goal-directed provability. It is a generalization of the logic programming style of deduction, and it is particularly favourable for proof search. The methodology is applied for the first time in a uniform way to a wide range of non-classical systems, covering intuitionistic, inte…Read more
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##### Abductive reasoning in neural-symbolic systems with Artur S. D’Avila Garcez, Oliver Ray, and John Woods Topoi 26 (1): 37-49. 2007.
Abduction is or subsumes a process of inference. It entertains possible hypotheses and it chooses hypotheses for further scrutiny. There is a large literature on various aspects of non-symbolic, subconscious abduction. There is also a very active research community working on the symbolic (logical) characterisation of abduction, which typically treats it as a form of hypothetico-deductive reasoning. In this paper we start to bridge the gap between the symbolic and sub-symbolic approaches to abdu…Read more
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##### Fibring Argumentation Frames Studia Logica 93 (2): 231-295. 2009.
This paper is part of a research program centered around argumentation networks and offering several research directions for argumentation networks, with a view of using such networks for integrating logics and network reasoning. In Section 1 we introduce our program manifesto. In Section 2 we motivate and show how to substitute one argumentation network as a node in another argumentation network. Substitution is a purely logical operation and doing it for networks, besides developing their theo…Read more
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##### Labelled Deductive Systems Oxford University Press. 1996.
This important book provides a new unifying methodology for logic. It replaces the traditional view of logic as manipulating sets of formulas with the notion of structured families of labelled formulas with algebraic structures. This approach has far reaching consequences for the methodology of logics and their semantics, and the book studies the main features of such systems along with their applications. It will interest logicians, computer scientists, philosophers and linguists.
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##### Size and logic with Karl Schlechta Review of Symbolic Logic 2 (2): 396-413. 2009.
We show how to develop a multitude of rules of nonmonotonic logic from very simple and natural notions of size, using them as building blocks
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##### Fibred Security Language with Guido Boella, Dov M. Gabbay, Valerio Genovese, and Leendert van der Torre Studia Logica 92 (3): 395-436. 2009.
We study access control policies based on the says operator by introducing a logical framework called Fibred Security Language (FSL) which is able to deal with features like joint responsibility between sets of principals and to identify them by means of first-order formulas. FSL is based on a multimodal logic methodology. We first discuss the main contributions from the expressiveness point of view, we give semantics for the language both for classical and intuitionistic fragment), we then prov…Read more
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##### A Comment on Work by Booth and Co-authors with Karl Schlechta Studia Logica 94 (3): 403-432. 2010.
Booth and his co-authors have shown in [2], that many new approaches to theory revision (with fixed K ) can be represented by two relations, , where is a sub-relation of &lt; . They have, however, left open a characterization of the infinite case, which we treat here.
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##### Dung’s Argumentation is Essentially Equivalent to Classical Propositional Logic with the Peirce–Quine Dagger Logica Universalis 5 (2): 255-318. 2011.
In this paper we show that some versions of Dung’s abstract argumentation frames are equivalent to classical propositional logic. In fact, Dung’s attack relation is none other than the generalised Peirce–Quine dagger connective of classical logic which can generate the other connectives ${\neg, \wedge, \vee, \to}$ of classical logic. After establishing the above correspondence we offer variations of the Dung argumentation frames in parallel to variations of classical logic, such as resource logi…Read more
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##### Łukasiewicz Logic: From Proof Systems To Logic Programming with George Metcalfe and Nicola Olivetti Logic Journal of the IGPL 13 (5): 561-585. 2005.
We present logic programming style “goal-directed” proof methods for Łukasiewicz logic Ł that both have a logical interpretation, and provide a suitable basis for implementation. We introduce a basic version, similar to goal-directed calculi for other logics, and make refinements to improve efficiency and obtain termination. We then provide an algorithm for fuzzy logic programming in Rational Pavelka logic RPL, an extension of Ł with rational constants