Vassar College Digital Library
The paper proposes a bimodal logic that describes an interplay between coalition strategies and distributed knowledge. Unlike the existing literature, the paper assumes that a strategy must be not only executable but also verifiable. That is, the strategy of a coalition should be based only on the information distributively known by the coalition and the coalition must be able to verify the result after the strategy is executed. The main technical result of the paper is a sound and complete logical system describing all universal properties expressible in the proposed bimodal language.