## DL-Lite: Tractable description logics for ontologies (2005)

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Venue: | In Proc. of AAAI 2005 |

Citations: | 170 - 46 self |

### BibTeX

@INPROCEEDINGS{Calvanese05dl-lite:tractable,

author = {Diego Calvanese and Domenico Lembo and Maurizio Lenzerini and Riccardo Rosati},

title = {DL-Lite: Tractable description logics for ontologies},

booktitle = {In Proc. of AAAI 2005},

year = {2005},

pages = {602--607}

}

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### Abstract

We propose a new Description Logic, called DL-Lite, specifically tailored to capture basic ontology languages, while keeping low complexity of reasoning. Reasoning here means not only computing subsumption between concepts, and checking satisfiability of the whole knowledge base, but also answering complex queries (in particular, conjunctive queries) over the set of instances maintained in secondary storage. We show that in DL-Lite the usual DL reasoning tasks are polynomial in the size of the TBox, and query answering is polynomial in the size of the ABox (i.e., in data complexity). To the best of our knowledge, this is the first result of polynomial data complexity for query answering over DL knowledge bases. A notable feature of our logic is to allow for a separation between TBox and ABox reasoning during query evaluation: the part of the process requiring TBox reasoning is independent of the ABox, and the part of the process requiring access to the ABox can be carried out by an SQL engine, thus taking advantage of the query optimization strategies provided by current DBMSs.

### Citations

1599 |
Foundations of Databases
- Abiteboul, Hull, et al.
(Show Context)
Citation Context ...r logic makes it suitable for expressing a variety of representation languages widely adopted in different contexts, such as basic ontology languages, conceptual data models (e.g., EntityRelationship =-=[2]-=-), and object-oriented formalisms (e.g., basic UML class diagrams 3 ). 2. For such a DL we propose novel reasoning techniques for a variety of tasks, including conjunctive query answering and containm... |

724 |
editors. The description logic handbook: theory, implementation, and applications
- Baader, Calvanese, et al.
- 2003
(Show Context)
Citation Context ...ling power required in capturing conceptual models and basic ontology languages, while most DLs with sufficient modeling power suffer from inherently worst-case exponential time behavior of reasoning =-=[4, 5]-=-. Although the requirement of polynomially tractable reasoning might be less stringent when dealing with relatively small ontologies, we believe that the need of efficient reasoning algorithms is of p... |

539 |
The complexity of relational query languages
- Vardi
- 1982
(Show Context)
Citation Context ... for query answering, computing the answers to a conjunctive query is worst-case exponential in the size of the TBox and the query, but is polynomial in the size of the ABox, i.e., in data complexity =-=[17]-=-. Hence, the complexity of answering queries is no worse than traditional query evaluation in relational databases 4 . A prototype implementation of DL-Lite has been developed and tested within a rese... |

358 | Classic: A structural data model for objects
- Borgida, Brachman, et al.
- 1989
(Show Context)
Citation Context ...n SQL engine over the ABox, thus taking advantage of well established query optimization strategies. Notably, this was one of the motivations behind several research works done on CLASSIC in the 80’s =-=[6]-=-. 4. We analyze the complexity of reasoning in DL-Lite. We show that the usual reasoning tasks considered in DLs (i.e., subsumption and satisfiability) can be done in polynomial time. As for query ans... |

303 | Consistent Query Answers in Inconsistent Databases
- Arenas, Bertossi, et al.
- 1999
(Show Context)
Citation Context ...ty [9]. Our work is also tightly related to work in databases on implication of integrity constraints (ICs) [2] and on query answering in the presence of ICs under an open world semantics (see, e.g., =-=[8, 3, 14, 7]-=-). Rephrased as ICs, DL-Lite TBoxes allow for expressing special forms of inclusion dependencies (i.e., ISA, role typing, and participation constraints), multiple keys on relations (i.e., functionalit... |

299 | Complexity of answering queries using materialized views
- Abiteboul, Duschka
- 1998
(Show Context)
Citation Context ...nd that make reasoning in OWL Lite non-tractable in general. Reasoning in DL-Lite It can be shown that query containment can be reformulated as query answering using techniques similar to the ones in =-=[1]-=-. Hence, we concentrate on query answering only. We first address some preliminary issues, and then we define the query reformulation algorithm PerfectRef, which is at the heart of our query evaluatio... |

151 | ALlog: integrating datalog and description logics
- Donini, Lenzerini, et al.
- 1998
(Show Context)
Citation Context ...e all EXPTIME-hard, and more importantly they are not tailoredstowards obtaining tight complexity bounds with respect to data complexity. Conjunctive queries combined with DLs were also considered in =-=[16, 13]-=-, but again data complexity was not the main concern. There has been a lot of work in DLs on the boundary between polynomial and exponential reasoning. This work first concentrated on DLs without the ... |

137 |
Combining Horn rules and description logics in CARIN
- Levy, Rousset
- 1998
(Show Context)
Citation Context ...e all EXPTIME-hard, and more importantly they are not tailoredstowards obtaining tight complexity bounds with respect to data complexity. Conjunctive queries combined with DLs were also considered in =-=[16, 13]-=-, but again data complexity was not the main concern. There has been a lot of work in DLs on the boundary between polynomial and exponential reasoning. This work first concentrated on DLs without the ... |

126 | On the Decidability and Complexity of Query Answering over Inconsistent and Incomplete Databases
- Cali, Lembo, et al.
- 2003
(Show Context)
Citation Context ...ty [9]. Our work is also tightly related to work in databases on implication of integrity constraints (ICs) [2] and on query answering in the presence of ICs under an open world semantics (see, e.g., =-=[8, 3, 14, 7]-=-). Rephrased as ICs, DL-Lite TBoxes allow for expressing special forms of inclusion dependencies (i.e., ISA, role typing, and participation constraints), multiple keys on relations (i.e., functionalit... |

106 | Recursive query plans for data integration
- Duschka, Genesereth, et al.
(Show Context)
Citation Context ...ty [9]. Our work is also tightly related to work in databases on implication of integrity constraints (ICs) [2] and on query answering in the presence of ICs under an open world semantics (see, e.g., =-=[8, 3, 14, 7]-=-). Rephrased as ICs, DL-Lite TBoxes allow for expressing special forms of inclusion dependencies (i.e., ISA, role typing, and participation constraints), multiple keys on relations (i.e., functionalit... |

91 | The Logic of Knowledge Bases
- Levesque, Lakemeyer
- 2001
(Show Context)
Citation Context ...cs of DL-Lite is given in terms of interpretations over a fixed infinite domain ∆. We assume to have one constant for each object, denoting exactly that object. In other words, we have standard names =-=[15]-=-, and we will not distinguish between the alphabet of constants and ∆. An interpretation I = (∆, · I ) consists of a first order structure over ∆ with an interpretation function · I such that: A I ⊆ ∆... |

78 | Deduction in concept languages: From subsumption to instance checking
- Donini, Lenzerini, et al.
- 1994
(Show Context)
Citation Context ...onally drop negated atomic concept), and ALU (where we introduce union and drop number restrictions), instance checking, and therefore conjunctive query answering, is coNP-complete in data complexity =-=[12]-=-. Indeed, the argument used in the proof of coNPhardness of ALE, FLE − , and ALU in [12], immediately implies the following theorem. Theorem 7 Answering conjunctive queries is coNP-hard in data comple... |

58 | Answering queries using views over description logics knowledge bases
- Calvanese, Giacomo, et al.
- 2000
(Show Context)
Citation Context ...roles) usually considered in DL research. Unfortunately, in these contexts, whenever the complexity of reasoning is exponential in the size of the instances (as for example in Fact 1 , Racer 2 and in =-=[11]-=-), there is little hope for effective instance management and query answering algorithms. In this paper we propose a new DL, called DL-Lite, specifically tailored to capture basic ontology languages, ... |

56 | Logic Programs for Consistently Querying Data Integration Systems
- Bravo, Bertossi
- 2003
(Show Context)
Citation Context |

42 |
Conceptual modeling with description logics
- Borgida, Brachman
(Show Context)
Citation Context ...ling power required in capturing conceptual models and basic ontology languages, while most DLs with sufficient modeling power suffer from inherently worst-case exponential time behavior of reasoning =-=[4, 5]-=-. Although the requirement of polynomially tractable reasoning might be less stringent when dealing with relatively small ontologies, we believe that the need of efficient reasoning algorithms is of p... |

37 | Reasoning with inclusion axioms in description logics: Algorithms and complexity
- Calvanese
- 1996
(Show Context)
Citation Context ...y; (3) union of concepts can appear in the right-hand side of inclusion assertions. If we allow for cyclic inclusion assertions in the KB, then even subsumption in CLASSIC and ALN becomes intractable =-=[9]-=- 7 . Observe that DL-Lite does allow for cyclic assertions without falling into intractability. Indeed, we can enforce the cyclic propagation of the existence of an Rsuccessor using the two DL-Lite in... |

20 | What to ask to a peer: ontology-based query reformulation
- Calvanese, Giacomo, et al.
- 2004
(Show Context)
Citation Context ...n-ary relations without loosing their nice computational properties. We are working on other interesting extensions to DL-Lite, such as the introduction of subset constraints on roles. The results of =-=[10]-=- imply that finding an adaptation of our query answering technique is going to be a hard problem. Acknowledgments This research has been partially supported by the Projects INFOMIX (IST-2001-33570) an... |