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A Relevance Terminological Logic for Information Retrieval
 IN PROCEEDINGS OF SIGIR96, 19TH INTERNATIONAL CONFERENCE ON RESEARCH AND DEVELOPMENT IN INFORMATION RETRIEVAL
, 1996
"... A Terminological Logic is presented as an information retrieval model, with a fourvalued semantics that gives to its inference relation the flavour of relevance, that is a strict connection in meaning between the premises and the conclusion of the arguments licensed by the logic. The logic also per ..."
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Cited by 35 (9 self)
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A Terminological Logic is presented as an information retrieval model, with a fourvalued semantics that gives to its inference relation the flavour of relevance, that is a strict connection in meaning between the premises and the conclusion of the arguments licensed by the logic. The logic also permits the expression of metaknowledge enforcing a closedworld reading of the knowledge concerning specified individuals and primitive concepts. A Gentzenstyle, sound and complete calculus for reasoning in the logic is given, thus establishing the basis for an information retrieval engine.
Reasoning about knowledge: An overview
 Proceedings of the 1986 Conference on Theoretical Aspects of Reasoning About Knowledge
, 1986
"... Abstract: In this overview paper, I will attempt to identify and describe some of the common threads that tie together work in reasoning about knowledge in such diverse fields as philosophy, economics, linguistics, artificial intelligence, and theoretical computer sciencce. I will briefly discuss so ..."
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Cited by 32 (3 self)
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Abstract: In this overview paper, I will attempt to identify and describe some of the common threads that tie together work in reasoning about knowledge in such diverse fields as philosophy, economics, linguistics, artificial intelligence, and theoretical computer sciencce. I will briefly discuss some of the more recent work, particularly in computer science, and suggest some lines for future research.
Entailed Ranking Arguments
, 2002
"... An ‘elementary ranking condition ’ (ERC) embodies the kind of restrictions imposed by a comparison between a desired optimum and a single competitor. All entailments between elementary ranking conditions can be ascertained through three simple formal rules; one of them introduces a method of argumen ..."
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Cited by 31 (3 self)
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An ‘elementary ranking condition ’ (ERC) embodies the kind of restrictions imposed by a comparison between a desired optimum and a single competitor. All entailments between elementary ranking conditions can be ascertained through three simple formal rules; one of them introduces a method of argument combination, fusion, shown to have the same sense as in relevance logic. Fusion is also central to detecting inconsistency in a set of ERCs; inconsistency and entailment are closely related here, much as in ordinary logic. Fusion therefore plays a key role in the definition of Recursive Constraint Demotion (RCD: Tesar & Smolensky 1994, 1998). When ERCs are hierarchized by the ranking of the constraints that crucially evaluate them, their entailment and fusional relations are seen to correlate with aspects of ranking structure. RCD and the Minimal Stratified Hierarchy it produces also figure prominently in an efficient procedure for calculating entailments. Harmonic bounding, both simple and collective, leads to the existence of entailment relations, and removal of entailment dependencies from a set of ERCs eliminates harmonic bounding in its underlying candidate set. The logic of entailment in OT is seen to be the implicationnegation fragment of RM (Sobociski 1952, Parks 1972) and the logic of OT in general is shown by a semantical argument to be precisely RM itself. When the logic is extended from ERCs to constraints, it allows for a direct representation of the notion of a strict domination hierarchy using only the connectives of the logic; various ranking restrictions are shown to follow when logical relations exist between constraints.
A Theory Of Justified Reformulations
, 1990
"... Present day systems, intelligent or otherwise, are limited by the conceptualizations of the world given to them by their designers. In this paper, we propose a novel, firstprinciples approach to performing incremental reformulations for computational efficiency. First, we define a reformulation to ..."
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Cited by 24 (0 self)
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Present day systems, intelligent or otherwise, are limited by the conceptualizations of the world given to them by their designers. In this paper, we propose a novel, firstprinciples approach to performing incremental reformulations for computational efficiency. First, we define a reformulation to be a shift in conceptualization: a change in the basic objects, functions, and relations assumed in a formulation. We then analyze the requirements for automating reformulation and show the need for justifying shifts in conceptualization. Inefficient formulations make irrelevant distinctions. A new class of metatheoretical justifications for a reformulation called irrelevance explanations, is presented. A logical irrelevance explanation demonstrates that certain distinctions made in the formulation are not necessary for the computation of a given class of problems. A computational irrelevance explanation shows that some distinctions are not useful with respect to a given problem solver fo...
Formal Approaches to Student Modelling
, 1994
"... This paper considers student modelling from the point of view of the formal techniques that are involved. It attempts to provide a theoretical, computational basis for student modelling which is psychologically neutral and independent of applications. It is derived mainly from various areas of the ..."
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Cited by 24 (2 self)
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This paper considers student modelling from the point of view of the formal techniques that are involved. It attempts to provide a theoretical, computational basis for student modelling which is psychologically neutral and independent of applications. It is derived mainly from various areas of theoretical artificial intelligence. Because of the intrinsic difficulty of the student modelling problem, these links to AI are often merely pointed out and not pursued in depth.
A Relevant Analysis of Natural Deduction
 Journal of Logic and Computation
, 1999
"... Linear and other relevant logics have been studied widely in mathematical, philosophical and computational logic. We describe a logical framework, RLF, for defining natural deduction presentations of such logics. RLF consists in a language together, in a manner similar to that of Harper, Honsell and ..."
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Cited by 23 (7 self)
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Linear and other relevant logics have been studied widely in mathematical, philosophical and computational logic. We describe a logical framework, RLF, for defining natural deduction presentations of such logics. RLF consists in a language together, in a manner similar to that of Harper, Honsell and Plotkin's LF, with a representation mechanism: the language of RLF is the lLcalculus; the representation mechanism is judgementsastypes, developed for relevant logics. The lLcalculus type theory is a firstorder dependent type theory with two kinds of dependent function spaces: a linear one and an intuitionistic one. We study a natural deduction presentation of the type theory and establish the required prooftheoretic metatheory. The RLF framework is a conservative extension of LF. We show that RLF uniformly encodes (fragments of) intuitionistic linear logic, Curry's l I calculus and ML with references. We describe the CurryHowardde Bruijn correspondence of the lLcalculus with a s...
Efficient Detection of Vacuity in Temporal Model Checking
 Formal Methods in System Design
, 2001
"... Abstract. The ability to generate a counterexample is an important feature of model checking tools, because a counterexample provides information to the user in the case that the formula being checked is found to be nonvalid. In this paper, we turn our attention to providing similar feedback to t ..."
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Cited by 22 (5 self)
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Abstract. The ability to generate a counterexample is an important feature of model checking tools, because a counterexample provides information to the user in the case that the formula being checked is found to be nonvalid. In this paper, we turn our attention to providing similar feedback to the user in the case that the formula is found to be valid, because valid formulas can hide real problems in the model. For instance, propositional logic formulas containing implications can suffer from antecedent failure, in which the formula is trivially valid because the precondition of the implication is not satisfiable. We call this vacuity, and extend the definition to cover other kinds of trivial validity. For nonvacuously valid formulas, we define an interesting witness as a nontrivial example of the validity of the formula. We formalize the notions of vacuity and interesting witness, and show how to detect vacuity and generate interesting witnesses in temporal model checking. Finally, we provide a practical solution for a useful subset of ACTL formulas.
Information Fusion in Logic: A Brief Overview
 In Symbolic and Quantitative Approaches to Uncertainty, Lecture Notes in Computer Science
, 1997
"... . Information fusion is the process of deriving a single consistent knowledgebase from multiple knowledgebases. This process is important in many cognitive tasks such as decisionmaking, planning, design, and specification, that can involve collecting information from a number of potentially conflic ..."
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Cited by 22 (5 self)
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. Information fusion is the process of deriving a single consistent knowledgebase from multiple knowledgebases. This process is important in many cognitive tasks such as decisionmaking, planning, design, and specification, that can involve collecting information from a number of potentially conflicting perspectives or sources, or participants. In this brief overview, we focus on the problem of inconsistencies arising in information fusion. In the following, we consider reasoning with inconsistencies, acting on inconsistencies, and resolving inconsistencies. 1 Introduction Many tasks that an intelligent agent performs such as decisionmaking, planning, design, and specification, often involve collecting information from a number of potentially conflicting perspectives or sources, or participants with different views, and forming a single combined view or perspective  a synthesis, or consensus. Consider requirements engineering. The development of most large and complex systems nece...
Steps towards a firstorder logic of explicit and implicit belief
 Theoretical Aspects of Reasoning About Knowledge: Proceedings of the 1986 Conference
, 1986
"... Modelling the beliefs of an agent who lacks logical omniscience has been a major concern recently. While most of the work has concentrated on propositional logics of belief, this paper primarily addresses issues raised by adding quantifiers to such logics. In particular, we are focusing on quantifyi ..."
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Cited by 21 (1 self)
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Modelling the beliefs of an agent who lacks logical omniscience has been a major concern recently. While most of the work has concentrated on propositional logics of belief, this paper primarily addresses issues raised by adding quantifiers to such logics. In particular, we are focusing on quantifying in and the distinction between "knowing what " and "knowing that". After arguing why a model of limited reasoning should preserve this distinction, we show how this can be accomplished by a semantics based on a restricted form of tautological entailment.
What is an Inference Rule?
 Journal of Symbolic Logic
, 1992
"... What is an inference rule? This question does not have a unique answer. One usually nds two distinct standard answers in the literature: validity inference ( ` v ' if for every substitution , the validity of [] entails the validity of [']), and truth inference ( ` t ' if for every substitution , ..."
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Cited by 19 (2 self)
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What is an inference rule? This question does not have a unique answer. One usually nds two distinct standard answers in the literature: validity inference ( ` v ' if for every substitution , the validity of [] entails the validity of [']), and truth inference ( ` t ' if for every substitution , the truth of [] entails the truth of [']). In this paper we introduce a general semantic framework that allows us to investigate the notion of inference more carefully. Validity inference and truth inference are in some sense the extremal points in our framework. We investigate the relationship between various types of inference in our general framework, and consider the complexity of deciding if an inference rule is sound, in the context of a number of logics of interest: classical propositional logic, a nonstandard propositional logic, various propositional modal logics, and rstorder logic.