Tangent Circle Algebras
نویسندگان
چکیده
In relational reasoning, one is concerned with the algebras generated by a given set of relations, when one allows only basic relational operations such as the Boolean operations, relational composition, and converse. According to a result by A. Tarski, the relations obtained in this way are exactly the relations which are definable in the three–variable fragment of first order logic. Thus, a relation algebra is a first indicator of the expressive power of a given set of relations. In this paper, we investigate relation algebras which arise in the context of preference relations. In particular, we study the tangent circle orders introduced by Abbas & Vincke [2].
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