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14
Conceptual Graphs: fundamental notions
 Revue d'Intelligence Artificielle
, 1992
"... . We state precise definitions of the basic notions of Sowa's framework [Sowa 84] and provide related results. These results mainly concern the structure of the specialization relation, correspondence between graph operations and logical operations, and algorithmic complexity of the model handling. ..."
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. We state precise definitions of the basic notions of Sowa's framework [Sowa 84] and provide related results. These results mainly concern the structure of the specialization relation, correspondence between graph operations and logical operations, and algorithmic complexity of the model handling. RESUME. Nous dfinissons prcisment les notions de base du modle des graphes conceptuels de Sowa [Sowa 84] et en tudions les proprits. Nos rsultats portent principalement sur la structure de la relation de spcialisation, la correspondance entre oprations de graphes et oprations logiques, et la complexit algorithmique de la mise en oeuvre du modle. KEY WORDS : Knowledge representation, conceptual graphs, Sowa's graphs, semantic networks, specialization / generalization, graphs, pattern matching, first order logic, algorithmic complexity. MOTSCLES : reprsentation de connaissances, graphes conceptuels, graphes de Sowa, rseaux smantiques, spcialisation / gnralisation, graphes, appariement, log...
Tractable and Decidable Fragments of Conceptual Graphs
 IN PROCEEDINGS OF ICCS'99
, 1999
"... It is wellknown that problems like validity and subsumption of general CGs are undecidable, whereas subsumption is NPcomplete for simple conceptual graphs (SGs) and tractable for SGs that are trees. We will employ results on decidable fragments of rstorder logic to identify a natural and expressi ..."
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Cited by 14 (0 self)
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It is wellknown that problems like validity and subsumption of general CGs are undecidable, whereas subsumption is NPcomplete for simple conceptual graphs (SGs) and tractable for SGs that are trees. We will employ results on decidable fragments of rstorder logic to identify a natural and expressive fragment of CGs for which validity and subsumption is decidable in ExpTime. In addition, we will extend existing work on the connection between SGs and description logics (DLs) by identifying a DL that corresponds to the class of SGs that are trees. This yields a tractability result previously unknown in the DL community.
Acquisition And Structuring Of An Ontology Within Conceptual Graphs
 University of Maryland, College Park, MD
, 1994
"... The elicitation of the ontology  i.e. the objects of a domain  is a key issue of conceptual modelling and therefore of knowledge acquisition. The Conceptual Graph Theory provides a knowledge representation formalism to be used in knowledgebased systems with an explicit "type lattice" to accou ..."
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Cited by 14 (1 self)
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The elicitation of the ontology  i.e. the objects of a domain  is a key issue of conceptual modelling and therefore of knowledge acquisition. The Conceptual Graph Theory provides a knowledge representation formalism to be used in knowledgebased systems with an explicit "type lattice" to account for the ontology. Since knowledge is in most AI applications non formal, it has to be normalized to ensure that the formal exploitation of its representation conforms to its meaning in the domain. Noting the intensional nature of types, which reflect the essences of the objects they denote, this normalization relies on a commitment on type definitions by necessary and sufficient conditions at the knowledge level. Our claim is that the taxonomic structure that accounts for the intensional nature of the ontology can be nothing but a tree, precluding tangled taxonomies. From this starting point, we derive methodological principles to constrain the acquisition of the "type tree", thus...
Conceptual Graphs are also Graphs
 LIRMM (CNRS & Universite de Montpellier II), 161, rue Ada, 34392 Montpellier Cedex 5
, 1995
"... . The main objective of this paper is to add one more brick in building the CG model as a knowledge representation model autonomous from logic. The CG model is not only a graphical representation of logic, it is much more: it is a declarative model encoding knowledge in a mathematical theory, na ..."
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. The main objective of this paper is to add one more brick in building the CG model as a knowledge representation model autonomous from logic. The CG model is not only a graphical representation of logic, it is much more: it is a declarative model encoding knowledge in a mathematical theory, namely labelled graph theory, which has efficient computable forms, with a fundamental graph operation on the encodings to do reasoning, projection, which is a labelled graph morphism. Main topics of this paper are: a generalized formalism for simple CGs; a strong equivalence between CSP (Constraint Satisfaction Problem) and labelled graph morphism. This correspondence allows the transportation of efficient algorithms from one domain to the other, and confirms that projection or more generally labelled graph morphism firmly moors CGs to combinatorial algorithmics, which is a cornerstone of computer science. The usual sound and complete first order logic semantics for CGs is stil...
RDF with regular expressions
 Research report 6191, INRIA RhôneAlpes, Grenoble (FR
, 2007
"... apport de recherche ..."
The CORALI Project: From Conceptual Graphs to Conceptual Graphs via Labelled Graphs
 in Proceedings of the Fifth International Conference on Conceptual Structures, ICCS'97
, 1997
"... . The scientific objectives of the "COnceptual gRAphs at LIrmm" project and the method used to reach these objectives are presented. 1 Introduction Sowa proposed the conceptual graphs model, in the data base context, in [4], and then developed it with a very large scope in his 1984 seminal book [5]. ..."
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. The scientific objectives of the "COnceptual gRAphs at LIrmm" project and the method used to reach these objectives are presented. 1 Introduction Sowa proposed the conceptual graphs model, in the data base context, in [4], and then developed it with a very large scope in his 1984 seminal book [5]. Sowa's multiple interests (e.g., linguistics, logics, computer science, artificial intelligence, philosophy) led to a multifaceted and highly diversified CG community. A look at the impressive bibliography compiled by Wermelinger clearly shows this, and therefore we will not present our views on all aspects of the CG model. This paper is simply aimed at presenting the scientific objectives of the "COnceptual gRAphs at LIrmm" project, and the method used to reach these objectives. Some of our results were presented during ICCS, others were presented elsewhere, or only published in French. I hope that this presentation of the overall picture will fill some holes. Prior to the CORALI project t...
Conceptual Graphs Isomorphism: Algorithm and Use
 In Proceedings of the 4th International Conference on Conceptual Structures, ICCS'96
, 1996
"... . The isomorphism problem is neither known to be NPcomplete nor polynomial. Yet it is crucial for managing large conceptual graph sets. In order to speed up the conceptual graph isomorphism test, we associate to graphs a textual code that is invariant under isomorphism: a structural or filterin ..."
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. The isomorphism problem is neither known to be NPcomplete nor polynomial. Yet it is crucial for managing large conceptual graph sets. In order to speed up the conceptual graph isomorphism test, we associate to graphs a textual code that is invariant under isomorphism: a structural or filtering code. The structural code of a given graph is based on the computation by a structural function of an intrinsic total preorder on its conceptual vertices. Moreover for graphs for which the structural function produces a total order on conceptual vertices, two graphs which have the same code are isomorphic. Then, we present a conceptual graph set managing system based on the specialization relation and on a hashing function on the code induced by a structural C preordering function. This system allows an effective search for a given conceptual graph according to its structure and so determines its specialization / generalization graphs without any projection test. 1 Introduction ...
Conceptual Graphs as Terms: Prospects for Resolution Theorem Proving
 Vrije Universiteit Amsterdam
, 1997
"... This thesis describes an attempt to employ conceptual graphs in a new way. In the past conceptual graphs have always been regarded as existentially quantified logic sentences. The intuition that conceptual graphs generalize feature structures inspires an alternative interpretation of CGs as "descrip ..."
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This thesis describes an attempt to employ conceptual graphs in a new way. In the past conceptual graphs have always been regarded as existentially quantified logic sentences. The intuition that conceptual graphs generalize feature structures inspires an alternative interpretation of CGs as "descriptions of objects in some domain", which we claim to be at least as appealing and intuitive as the traditional interpretation of CGs as first order logic sentences. With this new interpretation in mind, we examine the prospects of a resolution based theorem prover or logic programming language over a logic with CGs as its terms rather than sentences. Similar programming languages exist with feature structures as terms. We investigate the resolution proof procedure and the conceptual graph and feature structure formalisms, to arrive at the conclusion that for our purposes CGs are a valid extension of both feature structures and regular first order logic terms. We then prove that for CGs, in ge...
Using Ontologies to Index Conceptual Structures for Tendering Automation
 of the Secretary of Labor. K.15 52.2231 CLEAN AIR AND WATER CERTIFICATION (APR
, 1984
"... Using natural language to model the tendering makes any process associated with tendering automation extremely difficult. Conceptual Graph is a wellknown mechanism for knowledge representation. We implemented our ontologics using CGs. In tendering domain, we define two ontologics: The Tendering Str ..."
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Using natural language to model the tendering makes any process associated with tendering automation extremely difficult. Conceptual Graph is a wellknown mechanism for knowledge representation. We implemented our ontologics using CGs. In tendering domain, we define two ontologics: The Tendering Structure and the Abstract Domain Ontology. In this paper we survey the indexing and retrieving techniques in CG literatures. Then we build a slight modification of these techniques to build our own indexing technique using these ontologics. Using this technique enables us to define different type of matchmaking. Also to define finding policies to direct software agents in retrieving process.
Compilation and Approximation of Conjunctive Queries by Concept Descriptions
, 2002
"... In this paper, we characterize the logical correspondence between conjunctive queries and concept descriptions. We exhibit a necessary and sufficient condition for the compilation of a conjunctive query into an equivalent ALE concept description. We provide a necessary and sufficient condition for t ..."
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In this paper, we characterize the logical correspondence between conjunctive queries and concept descriptions. We exhibit a necessary and sufficient condition for the compilation of a conjunctive query into an equivalent ALE concept description. We provide a necessary and sufficient condition for the approximation of conjunctive queries by maximally subsumed ALN concept descriptions.