  Game logic is a dynamic modal logic which models strategic two person games;
it contains propositional dynamic logic (PDL) as a fragment. We propose an
interpretation of game logic based on stochastic effectivity functions. A
definition of these functions is proposed, and some algebraic properties of
effectivity functions such as congruences are investigated. The relationship to
stochastic relations is characterized through a deduction system. Logical and
behavioral equivalence of game models is investigated. Finally the completion
of models receives some attention.
