The What-To-Ask Problem for Ontology-Based Peers

Diego Calvanese, Giuseppe De Giacomo, Domenico Lembo, Maurizio Lenzerini, and Riccardo Rosati

Description Logic, Theory Combination, and All That -- Essays Dedicated to Franz Baader on the Occasion of his 60th Birthday. Volume 11560 of Lecture Notes in Computer Science. 2019.

The issue of cooperation, integration, and coordination between information peers has been addressed over the years both in the context of the Semantic Web and in several other networked environments, including data integration, Peer-to-Peer and Grid computing, service-oriented computing, distributed agent systems, and collaborative data sharing. One of the main problems arising in such contexts is how to exploit the mappings between peers in order to answer queries posed to one peer. We address this issue for peers managing data through ontologies and in particular focus on ontologies specified in logics of the DL-Lite family. Our goal is to present some basic, fundamental results on this problem. In particular, we focus on a simplified setting based on just two interoperating peers, and we investigate how to solve the so-called "What-To-Ask" problem: find a way to answer queries posed to a peer by relying only on the query answering service available at the queried peer and at the other peer. We show both a positive and a negative result. Namely, we first prove that a solution to this problem always exists when the ontology is specified in DL- LiteR , andweprovideanalgorithmtocomputeit.T hen, weshowthatf orthecaseof DL- LiteF theproblemmayhavenosolution.W ef inallyillustratethatasolutiontoourproblemcanstillbef oundevenf ormoregeneralnetworksof peers* *, andf oranylanguageof theDL- Litef amily, providedthatweinterpretmappingsaccordingtoanepistemicsemantics, ratherthantheusualf irst- ordersemantics.

   title = "The What-To-Ask Problem for Ontology-Based Peers",
   year = "2019",
   author = "Diego Calvanese and De Giacomo, Giuseppe and Domenico
Lembo and Maurizio Lenzerini and Riccardo Rosati",
   booktitle = "Description Logic, Theory Combination, and All That -- Essays
Dedicated to Franz Baader on the Occasion of his 60th Birthday",
   pages = "187--211",
   volume = "11560",
   publisher = "Springer",
   series = "Lecture Notes in Computer Science",
   doi = "10.1007/978-3-030-22102-7_9",