Common knowledge revisited
  We consider the common-knowledge paradox raised by Halpern and Moses: common knowledge is necessary for agreement and coordination, but common knowledge is unattainable in the real world because of temporal imprecision. We discuss two solutions to this paradox: (1) modeling the world with a coarser granularity, and (2) relaxing the requirements for coordination. 
R. Fagin, J. Y. Halpern, Y. Moses, and M. Vardi