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Alexander Rabinovich - One of the best experts on this subject based on the ideXlab platform.
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No Future without (a hint of) Past
Information and Computation, 2016Co-Authors: Dorit Pardo, Alexander RabinovichAbstract:Kamp's theorem established the Expressive Completeness of the temporal modalities Until and Since for the First-Order Monadic Logic of Order (FOMLO) over real and natural time flows. Over natural time, a single future modality (Until) is sufficient to express all future FOMLO formulas. These are formulas whose truth value at any moment is determined by what happens from that moment on. Yet this fails to extend to real time domains: here no finite basis of future modalities can express all future FOMLO formulas. In this paper we show that finiteness can be recovered if we slightly soften the requirement that future formulas must be totally past-independent: we allow formulas to depend just on the arbitrarily recent past, and maintain the requirement that they be independent of the rest - actually - of most of the past. We call them 'almost future' formulas, and show that there is a finite basis of almost future modalities which is Expressively complete (over all Dedekind complete time flows) for the almost future fragment of FOMLO.
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Fields of Logic and Computation II - On Almost Future Temporal Logics
Fields of Logic and Computation II, 2015Co-Authors: Alexander RabinovichAbstract:Kamp’s theorem established the Expressive Completeness of the temporal modalities Until and Since for the First-Order Monadic Logic of Order (FOMLO) over real and natural time flows. Over natural time, a single future modality (Until) is sufficient to express all future FOMLO formulas. These are formulas whose truth value at any moment is determined by what happens from that moment on. Yet this fails to extend to real time domains: here no finite basis of future modalities can express all future FOMLO formulas. Almost future formulas extend future formulas; they depend just on the very near past, and are independent of the rest of the past. For almost future formulas finiteness is recovered over Dedekind complete time flows. In this paper we show that there is no temporal logic with finitely many modalities which is Expressively complete for the almost future fragment of FOMLO over all linear flows.
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MFCS - A finite basis for ‘almost future' temporal logic over the reals
Mathematical Foundations of Computer Science 2012, 2012Co-Authors: Dorit Pardo, Alexander RabinovichAbstract:Kamp's theorem established the Expressive Completeness of the temporal modalities Until and Since for the First-Order Monadic Logic of Order (FOMLO) over Real and Natural time flows. Over Natural time, a single future modality (Until) is sufficient to express all future FOMLO formulas. These are formulas whose truth value at any moment is determined by what happens from that moment on. Yet this fails to extend to Real time domains: Here no finite basis of future modalities can express all future FOMLO formulas. In this paper we show that finiteness can be recovered if we slightly soften the requirement that future formulas must be totally past-independent: We allow formulas to depend just on the very very near-past, and maintain the requirement that they be independent of the rest - actually - of most of the past. We call them ‘almost future' formulas, and show that there is a finite basis of almost future modalities which is Expressively complete over the Reals for the almost future fragment of FOMLO.
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CONCUR - Expressive Power of Temporal Logics
CONCUR 2002 — Concurrency Theory, 2002Co-Authors: Alexander RabinovichAbstract:The objectives of this paper is to survey classical and recent Expressive Completeness results and to provide some external yardsticks by which the Expressive power of temporal logics can be measured.
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Expressive power of temporal logics
Lecture Notes in Computer Science, 2002Co-Authors: Alexander RabinovichAbstract:The objectives of this paper is to survey classical and recent Expressive Completeness results and to provide some external yardsticks by which the Expressive power of temporal logics can be measured.
Jia-huai You - One of the best experts on this subject based on the ideXlab platform.
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IJCAI - Expressive Completeness of existential rule languages for ontology-based query answering
2016Co-Authors: Heng Zhang, Yan Zhang, Jia-huai YouAbstract:Existential rules, also known as data dependencies in Databases, have been recently rediscovered as a promising family of languages for Ontology-based Query Answering. In this paper, we prove that disjunctive embedded dependencies exactly capture the class of recursively enumerable ontologies in Ontology-based Conjunctive Query Answering (OCQA). Our Expressive Completeness result does not rely on any built-in linear order on the database. To establish the Expressive Completeness, we introduce a novel semantic definition for OCQA ontologies. We also show that neither the class of disjunctive tuple-generating dependencies nor the class of embedded dependencies is Expressively complete for recursively enumerable OCQA ontologies.
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Expressive Completeness of Existential Rule Languages for Ontology-based Query Answering
arXiv: Artificial Intelligence, 2016Co-Authors: Heng Zhang, Yan Zhang, Jia-huai YouAbstract:Existential rules, also known as data dependencies in Databases, have been recently rediscovered as a promising family of languages for Ontology-based Query Answering. In this paper, we prove that disjunctive embedded dependencies exactly capture the class of recursively enumerable ontologies in Ontology-based Conjunctive Query Answering (OCQA). Our Expressive Completeness result does not rely on any built-in linear order on the database. To establish the Expressive Completeness, we introduce a novel semantic definition for OCQA ontologies. We also show that neither the class of disjunctive tuple-generating dependencies nor the class of embedded dependencies is Expressively complete for recursively enumerable OCQA ontologies.
Heng Zhang - One of the best experts on this subject based on the ideXlab platform.
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IJCAI - Expressive Completeness of existential rule languages for ontology-based query answering
2016Co-Authors: Heng Zhang, Yan Zhang, Jia-huai YouAbstract:Existential rules, also known as data dependencies in Databases, have been recently rediscovered as a promising family of languages for Ontology-based Query Answering. In this paper, we prove that disjunctive embedded dependencies exactly capture the class of recursively enumerable ontologies in Ontology-based Conjunctive Query Answering (OCQA). Our Expressive Completeness result does not rely on any built-in linear order on the database. To establish the Expressive Completeness, we introduce a novel semantic definition for OCQA ontologies. We also show that neither the class of disjunctive tuple-generating dependencies nor the class of embedded dependencies is Expressively complete for recursively enumerable OCQA ontologies.
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Expressive Completeness of Existential Rule Languages for Ontology-based Query Answering
arXiv: Artificial Intelligence, 2016Co-Authors: Heng Zhang, Yan Zhang, Jia-huai YouAbstract:Existential rules, also known as data dependencies in Databases, have been recently rediscovered as a promising family of languages for Ontology-based Query Answering. In this paper, we prove that disjunctive embedded dependencies exactly capture the class of recursively enumerable ontologies in Ontology-based Conjunctive Query Answering (OCQA). Our Expressive Completeness result does not rely on any built-in linear order on the database. To establish the Expressive Completeness, we introduce a novel semantic definition for OCQA ontologies. We also show that neither the class of disjunctive tuple-generating dependencies nor the class of embedded dependencies is Expressively complete for recursively enumerable OCQA ontologies.
Morgan Deters - One of the best experts on this subject based on the ideXlab platform.
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Expressive Completeness of separation logic with two variables and no separating conjunction
ACM Transactions on Computational Logic, 2016Co-Authors: Stephane Demri, Morgan DetersAbstract:Separation logic is used as an assertion language for Hoare-style proof systems about programs with pointers, and there is an ongoing quest for understanding its complexity and Expressive power. Herein, we show that first-order separation logic with one record field restricted to two variables and the separating implication (no separating conjunction) is as Expressive as weak second-order logic, substantially sharpening a previous result. Capturing weak second-order logic with such a restricted form of separation logic requires substantial updates to known proof techniques. We develop these and, as a by-product, identify the smallest fragment of separation logic known to be undecidable: first-order separation logic with one record field, two variables, and no separating conjunction. Because we forbid ourselves the use of many syntactic resources, this underscores even further the power of separating implication on concrete heaps.
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Expressive Completeness of separation logic with two variables and no separating conjunction
Logic in Computer Science, 2014Co-Authors: Stephane Demri, Morgan DetersAbstract:We show that first-order separation logic with one record field restricted to two variables and the separating implication (no separating conjunction) is as Expressive as weak second-order logic, substantially sharpening a previous result. Capturing weak second-order logic with such a restricted form of separation logic requires substantial updates to known proof techniques. We develop these, and as a by-product identify the smallest fragment of separation logic known to be undecidable: first-order separation logic with one record field, two variables, and no separating conjunction.
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CSL-LICS - Expressive Completeness of separation logic with two variables and no separating conjunction
Proceedings of the Joint Meeting of the Twenty-Third EACSL Annual Conference on Computer Science Logic (CSL) and the Twenty-Ninth Annual ACM IEEE Symp, 2014Co-Authors: Stephane Demri, Morgan DetersAbstract:We show that first-order separation logic with one record field restricted to two variables and the separating implication (no separating conjunction) is as Expressive as weak second-order logic, substantially sharpening a previous result. Capturing weak second-order logic with such a restricted form of separation logic requires substantial updates to known proof techniques. We develop these, and as a by-product identify the smallest fragment of separation logic known to be undecidable: first-order separation logic with one record field, two variables, and no separating conjunction.
Bernhard Heinemann - One of the best experts on this subject based on the ideXlab platform.
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Expressive Completeness of modal logic on binary ramified frames
Journal of Applied Non-Classical Logics, 1996Co-Authors: Bernhard HeinemannAbstract:ABSTRACT We characterize those binary ramified frames for which propositional modal logic is as Expressive as the corresponding first-order logic.
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on Expressive Completeness of modal logic
Foundations of Computer Science, 1994Co-Authors: Bernhard HeinemannAbstract:We have studied the problem of Expressive Completeness for modal logic. In case of a simple class of frames, the homogeneous ones, Expressive Completeness could be shown. Moreover, within a class of special finite hamiltonian binary ramified frames, called wheels, the complete ones have been classified by means of simple numerical invariants.
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LFCS - On Expressive Completeness of Modal Logic
Logical Foundations of Computer Science, 1994Co-Authors: Bernhard HeinemannAbstract:We have studied the problem of Expressive Completeness for modal logic. In case of a simple class of frames, the homogeneous ones, Expressive Completeness could be shown. Moreover, within a class of special finite hamiltonian binary ramified frames, called wheels, the complete ones have been classified by means of simple numerical invariants.
