Min-Based Fusion of Possibilistic DL-Lite Knowledge Bases

DL-Lite is one of the most important tractable fragment of DLs that provides a powerful framework to compactly encode available knowledge with a low computational complexity of the reasoning process. In semantic web area, merging different and often conflicting sources of information, has been recognized as an important problem. Pieces of information to be combined are provided with uncertainty due for instance to the reliability of sources. Possibility theory offers an important tool for representing and reasoning with uncertain, partial and inconsistent pieces of information. This paper first presents possibilistic DL-Lite, denoted by π-DL-Lite as an extension of DL-Lite within a possibility theory setting. It then focuses on the use of a minimum-based (min-based) operator, well known as idempotent conjunctive operator to combine π-DLLite possibility distributions and it shows that the semantic fusion of π-DL-Lite possibility distributions has a natural syntactic counterpart when dealing with π-DL-Lite knowledge bases. The min-based fusion operator is recommended when distinct sources that provide information are dependent.