s for Multi-Agent Only Knowing (extended abstract) Arild Waaler1,2 and Bjørnar Solhaug3,4 1 Finnmark College, Norway 2 Dep. of Informatics, University of Oslo, Norway 3 SINTEF ICT, Norway 4 Dep. of Information Science and Media Studies, University of Bergen, Norway The paper presents a Kripke semantics for a multi-agent generalization of Levesque’s logic of “only knowing”. We prove soundness and completeness and show that the logic has the Finite model property. The logic satisfies a Modal reduction theorem to the effect that any complex syntactical representation can be syntactically reduced to a provably equivalent form which directly reflects all the models of the representation. The model theory is illustrated by means of an example of supernormal defaults in a multi-agent language.