Unification in Description Logic EL without top constructor
نویسنده
چکیده
In recent years, the description logic EL has received a significant interest. The description logic EL is a knowledge representation formalism used e.g in natural language processing, configuration of technical systems, databases and biomedical ontologies. Unification is used there as a tool to recognize equivalent concepts. It has been proven that unification in EL is NP-complete. This result was based on a locality property of certain EL unifiers. Here we show that a similar locality holds for EL without top (EL-top), but decidability of EL-top unification does not follow immediately from locality as it does in the case of unification in EL. However, by restricting further the locality property, we prove that EL-top unification is decidable and construct an NExpTime decision procedure for the problem. Furthermore, we show that unification in EL-top is PSPACE-hard by reducing the Finite State Automata Intersection problem to EL-top unification problem.
منابع مشابه
Deciding Unifiability and Computing Local Unifiers in the Description Logic EL without Top Constructor
Unification in Description Logics has been proposed as a novel inference service that can, for example, be used to detect redundancies in ontologies. The inexpressive description logic EL is of particular interest in this context since, on the one hand, several large biomedical ontologies are defined using EL. On the other hand, unification in EL has been shown to be NP-complete, and thus of co...
متن کاملUnification in the Description Logic EL Without Top Constructor
Unification in Description Logics has been proposed as a novel inference service that can, for example, be used to detect redundancies in ontologies. The inexpressive Description Logic EL is of particular interest in this context since, on the one hand, several large biomedical ontologies are defined using EL. On the other hand, unification in EL has recently been shown to be NP-complete, and t...
متن کاملUnification in the Description Logic EL without the Top Concept
Unification in Description Logics has been proposed as a novel inference service that can, for example, be used to detect redundancies in ontologies. The inexpressive Description Logic EL is of particular interest in this context since, on the one hand, several large biomedical ontologies are defined using EL. On the other hand, unification in EL has recently been shown to be NP-complete, and t...
متن کاملHybrid Unification in the Description Logic EL
The description logic EL belongs to the family of logic-based knowledge representation formalisms. It allows a user to define concepts with the help of concept names (Nc), role names (Nr) and constructors: conjunction (u), existential restriction (∃r.C for r ∈ Nr and a concept C) and top constructor (>). Unification in Description Logics has been introduced in [6]. A unification problem in such...
متن کاملComputing Local Unifiers in the Description Logic EL without the Top Concept
Unification in Description Logics (DLs) has been proposed in [7] as a novel inference service that can, for example, be used to detect redundancies in ontologies. For instance, assume that one knowledge engineer defines the concept of professors that are mothers as Person u Female u ∃child.> u ∃job.Professor, whereas another knowledge engineer represents this notion in a somewhat different way,...
متن کامل