Local Models Semantics, or contextual reasoning=locality+compatibility☆☆This paper is a substantially revised and extended version of a paper with the same title presented at the 1998 Knowledge Representation and Reasoning Conference (KR'98). The order of the names is alphabetical.

AbstractIn this paper we present a new semantics, called Local Models Semantics, and use it to provide a foundation to reasoning with contexts. This semantics captures and makes precise the two main intuitions underlying contextual reasoning: (i) reasoning is mainly local and uses only part of what is potentially available (e.g., what is known, the available inference procedures), this part is what we call context (of reasoning); however (ii) there is compatibility among the reasoning performed in different contexts. We validate our semantics by formalizing two important forms of contextual reasoning: reasoning with viewpoints and reasoning about belief