A note on compromise values

The aim of this note is to provide a unified theory of all compromise value s defined as the tau-value in cooperative game theory. The so-called covari ance property plays a crucial role in our approach and, related to this pro perty, a family of covariant compromise values is introduced. The mentioned characterization is obtained by means of the covariance, efficiency and ce rtain specific proportionality properties. We also prove that the Shapley v alue belongs to this family, when one is confined to the class of zero-norm alized games.