Zachary Heckle and Pavel Naumov
Armstrong's axioms were originally proposed to describe functional dependency between sets of attributes in relational databases. The database semantics of these axioms can be easily rephrased in terms of distributed knowledge in multi-agent systems. The paper proposes alternative semantics of the same axioms in terms of common knowledge. The main technical result of this work is soundness and completeness of Armstrong's axioms with respect to the proposed semantics. An important implication of this result is an unexpected duality between notions of distributed and common knowledge. [pdf]