Ontology Merging as Social Choice Daniele Porello, Ulle Endriss Abstract: The problem of merging several ontologies has important applications in the Semantic Web, medical ontology engineering, and other domains where information from several distinct sources needs to be integrated in a coherent manner. We propose to treat ontology merging as a problem of social choice, i.e., as a problem of aggregating the input of a set of individuals into an adequate collective decision, and we show how to apply the methodology of social choice theory in this new domain. We do this for the case of ontologies that are modelled using description logics. Specifically, we formulate a number of desirable properties for ontology merging procedures, we identify the incompatibility of some of these properties, and we define and analyse several concrete procedures.