Oriented Equational Logic Programming is Complete

Lynch, Christopher

doi:10.1006/jsco.1996.0075

Cited by 17 publications

(10 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The conditions that we use correspond to resolution with free selection [9,36,57]: a selection function chooses selected facts in each clause, and resolution is performed only on selected facts, that is, the clause R • F 0 R is generated only when the conclusion is selected in R and F 0 is selected in R .…”

Section: The Basic Algorithmmentioning

confidence: 99%

Automatic verification of correspondences for security protocols*

Blanchet

2009

JCS

168

179

View full text Add to dashboard Cite

We present a new technique for verifying correspondences in security protocols. In particular, correspondences can be used to formalize authentication. Our technique is fully automatic, it can handle an unbounded number of sessions of the protocol, and it is efficient in practice. It significantly extends a previous technique for the verification of secrecy. The protocol is represented in an extension of the pi calculus with fairly arbitrary cryptographic primitives. This protocol representation includes the specification of the correspondence to be verified, but no other annotation. This representation is then translated into an abstract representation by Horn clauses, which is used to prove the desired correspondence. Our technique has been proved correct and implemented. We have tested it on various protocols from the literature. The experimental results show that these protocols can be verified by our technique in less than 1 s. * This paper is an updated and extended version of [13] and [14].We mainly focus on the works that automatically verify correspondences and authentication for security protocols, without bounding the number of sessions.The NRL protocol analyzer [43,58], based on narrowing in rewriting systems, can verify correspondences defined in a rich language of logical formulae [70]. It is sound and complete, but does not always terminate. Our Horn clause representation is more abstract than the representation of NRL, which should enable us to terminate more often and be more efficient, while remaining precise enough to prove most desired properties.Gordon and Jeffrey designed a system named Cryptic for verifying authentication by typing in security protocols [47][48][49]. They handle shared-key and public-key cryptography. Our system allows more general cryptographic primitives (including hash functions and Diffie-Hellman key agreements). Moreover, in our system, no annotation is needed, whereas, in Cryptic, explicit type casts and checks have to be manually added. However, Cryptic has the advantage that type checking always terminates, whereas, in some rare cases, our analyzer does not.Bugliesi et al.[26] define another type system for proving authentication in security protocols. The main advantage of their system is that it is compositional: it allows one to prove independently the correctness of the code of each role of the protocol. However, the form of messages is restricted to certain tagged terms. This approach is compared with Cryptic in [25].Backes et al.[10] prove secrecy and authentication for security protocols, using an abstract-interpretation-based analysis. This analysis builds a causal graph, which captures the causality among program events; the security properties are proved by traversing this graph. This analysis can handle an unbounded number of sessions of the protocol; it always terminates, at the cost of additional abstractions, which may cause false attacks. It handles shared-key and public-key cryptography, but not Diffie-Hellman key agreements. It assumes that the mess...

show abstract

Section: The Basic Algorithmmentioning

confidence: 99%

Automatic verification of correspondences for security protocols*

Blanchet

2009

JCS

168

179

View full text Add to dashboard Cite

show abstract

“…Both RQR and RFS form the basis for the algorithm presented here. RFS is proven to be correct and complete on Horn clauses [11] however due to space limitations RFS will not be explained, we refer the reader to previous citations. RQR reduces the number of useless factorizations in RFS, queries generated and pro cessing time through several optimizations, the main one being the introduction of Skolem functions when an existen tial quantification occurs in the head of a clause, which was handled in previous approaches as a nameless variable.…”

Section: Related Obda Query Rewriting Approachesmentioning

confidence: 99%

“…Saturation in resolution with free selection has been proved to be correct and complete for Horn clauses [11]. In this paper we see that (1) some of these resolution rules can be applied before having any query, (2) that subsumed clauses can be deleted optimizing the process and (3) that resolution with free selection has still a degree of freedom that allows to introduce some heuristics optimizing the process further, along with (4) other optimizations for query rewriting that can be done at the implementation level of this resolution method.…”

Section: Resolution With Free Selectionmentioning

confidence: 99%

Engineering optimisations in query rewriting for OBDA

Mora

Corcho

2013

Proceedings of the 9th International Conference on Semantic Systems

View full text Add to dashboard Cite

Ontology-based data access (OBDA) systems use ontologies to provide views over relational databases. Most of these systems work with ontologies implemented in description logic families of reduced expressiveness, what allows applying efficient query rewriting techniques for query answering. In this paper we describe a set of optimisations that are applicable with one of the most expressive families used in this context (tLrU-O ). Our resulting system exhibits a behaviour that is comparable to the one shown by systems that handle less expressive logics. INTRODUCTIONOntology Based Data Access (OBDA) consists on superimposing a conceptual layer as a view to an underlying information system, which abstracts away from how that information is maintained in the data layer and provides inference capabilities [6]. Expressiveness comes at a cost in terms of computational complexity, and thus OBDA has traditionally been an expensive feature only interesting when the challenges to tackle were on par with the cost of the solution. Several languages have been proposed as interesting compromise solutions between expressiveness and tractability for OBDA: the DL-Lite family [5], which includes DL-Lite core , DL-Lite^ and DL-Lite-ji; the QL profile of OWL2 [8]; some families in Datalog± [4]; and the tLrU-O family [14].In this paper we focus on ECHTO¬ and propose a series of optimisations that can be carried out during the rewriting process, which we have implemented in our system kyrie. This paper is structured as follows: In section 2 we provide some background on DL families and approaches for OBDA query rewriting. In section 3 we introduce the algorithms involved in our approach. In section 4 we describe our optimisations for the query rewriting process for tLtU-U . In section 5 we evaluate the results obtained. Finally, in section 6 we draw some conclusions from the work performed and outline some foreseen further improvements in the rewriting process. BACKGROUNDNow we briefly describe the most relevant logics used for OBDA, and review implementations that use these logics. They are presented here in a chronological order. OBDA-related logicsIn this section we cite logics with special relevance in OBDA.In the examples a refers to a constant (individual), Bi refer to basic concepts (classes) and R refers to roles (properties).• The DL-Lite family diverged into logics DL-Lite-ji and DL-Lite^, both extending DL-Lite core , where concept inclusions are restricted to B\ C B2 and B\ C ¬B2. DL-Lite-ji includes subsumption (ISA) and disjointness assertions between roles and DL-Lite^ includes functionality restrictions on roles. These logics are first-order reducible with a tractable complexity [5].• The OWL2 QL profile was inspired by the DL-Lite family and designed to keep the complexity of rewriting low, considering first-order rewritability. As a summary of a more extensive comparison [1], the main differences with DL-Lite are the lack of number restrictions, functionality constraints and keys. Among the constructs in OWL ...

show abstract

“…Both RQR and RFS form the basis for the algorithm presented here. RFS is proven to be correct and complete on Horn clauses [14] however due to space limitations RFS will not be explained, we refer the reader to previous citations. RQR reduces the number of useless factorizations in RFS, queries generated and processing time through several optimisations, the main one being the introduc tion of Skolem functions when an existential quantification occurs in the head of a clause, which was handled in previous approaches as a nameless variable.…”

Section: Obda Query Rewriting Systemsmentioning

confidence: 99%

Towards a Systematic Benchmarking of Ontology-Based Query Rewriting Systems

Mora

Corcho

2013

Advanced Information Systems Engineering

View full text Add to dashboard Cite

Abstract. Query rewriting is one of the fundamental steps in ontologybased data access (OBDA) approaches. It takes as inputs an ontology and a query written according to that ontology, and produces as an output a set of queries that should be evaluated to account for the inferences that should be considered for that query and ontology. Different query rewriting systems give support to different ontology languages with varying expressiveness, and the rewritten queries obtained as an output do also vary in expressiveness. This heterogeneity has traditionally made it difficult to compare different approaches, and the area lacks in general commonly agreed benchmarks that could be used not only for such comparisons but also for improving OBDA support. In this paper we compile data, dimensions and measurements that have been used to evaluate some of the most recent systems, we analyse and characterise these assets, and provide a unified set of them that could be used as a starting point towards a more systematic benchmarking process for such systems. Finally, we apply this initial benchmark with some of the most relevant OBDA approaches in the state of the art.

show abstract

Oriented Equational Logic Programming is Complete

Cited by 17 publications

References 22 publications

Automatic verification of correspondences for security protocols*

Automatic verification of correspondences for security protocols*

Engineering optimisations in query rewriting for OBDA

Towards a Systematic Benchmarking of Ontology-Based Query Rewriting Systems

Contact Info

Product

Resources

About