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32
CUF  A Formalism for Linguistic Knowledge Representation
 Deliverable R.1.2A, DYANA
, 1993
"... We describe the formalism CUF (Comprehensive Unification Formalism), which has been designed as a tool for writing and making computational use of any kind of linguistic description ranging from phonology to pragmatics. The motivations for its major design decisions are discussed. CUF is an offsprin ..."
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Cited by 66 (3 self)
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We describe the formalism CUF (Comprehensive Unification Formalism), which has been designed as a tool for writing and making computational use of any kind of linguistic description ranging from phonology to pragmatics. The motivations for its major design decisions are discussed. CUF is an offspring of the line of theoryneutral universal grammar formalisms like PATRII [SUP + 83] and STUFII [BKU88, Dor91, DR91]. Like these it is based on defining feature structures and relations over these as encodings of linguistic principles and data. However, it is radically more expressive, since it allows the definition of arbitrary recursive relational dependencies without tying recursion to phrase structure rules. Complex restrictions needed in semantic interpretation like anaphora resolution and presupposition checking can thus be stated in the same description language as the syntactic restrictions, providing the basis for highly integrated linguistic processing. CUF can be roughly charact...
Combining Deduction and Model Checking into Tableaux and Algorithms for ConversePDL
 Information and Computation
, 1998
"... . This paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for ¯calculus. We prove the correctness and completeness of the calculus and illustrate its f ..."
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Cited by 57 (7 self)
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. This paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for ¯calculus. We prove the correctness and completeness of the calculus and illustrate its features. We also discuss the transformation of the tableaux method (naively NEXPTIME) into an EXPTIME algorithm. 1 Introduction Propositional Dynamic Logics (PDLs) are modal logics introduced in [10] to model the evolution of the computation process by describing the properties of states reached by programs during their execution [15, 24, 27]. Over the years, PDLs have been proved to be a valuable formal tool in Computer Science, Logic, Computational Linguistics, and Artificial Intelligence far beyond their original use for program verification (e.g. [4, 12, 14, 15, 24, 23]). In this paper we focus on ConversePDL (CPDL) [10], obtained from the basic logic PDL by adding the converse operat...
The Computational Complexity of Hybrid Temporal Logics
 Logic Journal of the IGPL
, 2000
"... In their simplest form, hybrid languages are propositional modal languages which can refer to states. They were introduced by Arthur Prior, the inventor of tense logic, and played an important role in his work: because they make reference to specic times possible, they remove the most serious obstac ..."
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Cited by 55 (11 self)
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In their simplest form, hybrid languages are propositional modal languages which can refer to states. They were introduced by Arthur Prior, the inventor of tense logic, and played an important role in his work: because they make reference to specic times possible, they remove the most serious obstacle to developing modal approaches to temporal representation and reasoning. However very little is known about the computational complexity of hybrid temporal logics. In this paper we analyze the complexity of the satisability problem of a number of hybrid temporal logics: the basic hybrid language over transitive frames; nominal tense logic over transitive frames, strict total orders, and transitive trees; nominal Until logic; and referential interval logic. We discuss the eects of including nominals, the @ operator, the somewhere modality E, and the dierence operator D. Adding nominals to tense logic leads for several frame{classes to an increase in complexity of the satisability pro...
EXPTIME tableaux for ALC
 ARTIFICIAL INTELLIGENCE
, 2000
"... The last years have seen two major advances in Knowledge Representation and Reasoning. First, many interesting problems (ranging from Semistructured Data to Linguistics) were shown to be expressible in logics whose main deductive problems are EXPTIMEcomplete. Second, experiments in automated reaso ..."
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Cited by 51 (3 self)
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The last years have seen two major advances in Knowledge Representation and Reasoning. First, many interesting problems (ranging from Semistructured Data to Linguistics) were shown to be expressible in logics whose main deductive problems are EXPTIMEcomplete. Second, experiments in automated reasoning have substantially broadened the meaning of “practical tractability”. Instances of realistic size for PSPACEcomplete problems are now within reach for implemented systems. Still, there is a gap between the reasoning services needed by the expressive logics mentioned above and those provided by the current systems. Indeed, the algorithms based on treeautomata, which are used to prove EXPTIMEcompleteness, require exponential time and space even in simple cases. On the other hand, current algorithms based on tableau methods can take advantage of such cases, but require double exponential time in the worst case. We propose a tableau calculus for the description logic ALC for checking the satisfiability of a concept with respect to a TBox with general axioms, and transform it into the first simple tableaubased decision procedure working in single exponential time. To guarantee the ease of implementation, we also discuss the effects that optimizations (propositional backjumping, simplification, semantic branching, etc.) might have on our complexity result, and introduce a few optimizations ourselves.
Talking About Trees
 In Proceedings of the 6th Conference of the European Chapter of the Association for Computational Linguistics
, 1993
"... In this paper we introduce a modal lan guage L T for imposing constraints on trees, and an extension LT(L r) for imposing con straints on trees decorated with feature structures. The motivation for introducing these languages is to provide tools for formalising grammatical frameworks perspic ..."
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Cited by 45 (3 self)
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In this paper we introduce a modal lan guage L T for imposing constraints on trees, and an extension LT(L r) for imposing con straints on trees decorated with feature structures. The motivation for introducing these languages is to provide tools for formalising grammatical frameworks perspicuously, and the paper illustrates this by showing how the leading ideas of arsa can be captured in LT(Lr).
On the Expressivity of Feature Logics with Negation, Functional Uncertainty, and Sort Equations
 JOURNAL OF LOGIC, LANGUAGE AND INFORMATION
, 1993
"... Feature logics are the logical basis for socalled unification grammars studied in computational linguistics. We investigate the expressivity of feature terms with negation and the functional uncertainty construct needed for the description of longdistance dependencies and obtain the following resu ..."
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Cited by 40 (12 self)
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Feature logics are the logical basis for socalled unification grammars studied in computational linguistics. We investigate the expressivity of feature terms with negation and the functional uncertainty construct needed for the description of longdistance dependencies and obtain the following results: satisfiability of feature terms is undecidable, sort equations can be internalized, consistency of sort equations is decidable if there is at least one atom, and consistency of sort equations is undecidable if there is no atom.
Hybrid Logics
"... This chapter provides a modern overview of the field of hybrid logic. Hybrid logics are extensions of standard modal logics, involving symbols that name individual states in models. The first results that are nowadays considered as part of the field date back to the early work of Arthur ..."
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Cited by 35 (10 self)
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This chapter provides a modern overview of the field of hybrid logic. Hybrid logics are extensions of standard modal logics, involving symbols that name individual states in models. The first results that are nowadays considered as part of the field date back to the early work of Arthur
Feature Logics
 HANDBOOK OF LOGIC AND LANGUAGE, EDITED BY VAN BENTHEM & TER MEULEN
, 1994
"... Feature logics form a class of specialized logics which have proven especially useful in classifying and constraining the linguistic objects known as feature structures. Linguistically, these structures have their origin in the work of the Prague school of linguistics, followed by the work of Chom ..."
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Cited by 33 (0 self)
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Feature logics form a class of specialized logics which have proven especially useful in classifying and constraining the linguistic objects known as feature structures. Linguistically, these structures have their origin in the work of the Prague school of linguistics, followed by the work of Chomsky and Halle in The Sound Pattern of English [16]. Feature structures have been reinvented several times by computer scientists: in the theory of data structures, where they are known as record structures, in artificial intelligence, where they are known as frame or slotvalue structures, in the theory of data bases, where they are called "complex objects", and in computati
Tableaux and Algorithms for Propositional Dynamic Logic with Converse
 Proc. CADE13, LNAI 1104
, 1996
"... This paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for mucalculus. We prove the correctness and completeness of the calculus and illustrate its fe ..."
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Cited by 20 (6 self)
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This paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for mucalculus. We prove the correctness and completeness of the calculus and illustrate its features. We also discuss the transformation of the tableaux method (naively NEXPTIME) into an EXPTIME algorithm.