Contingency-Based Equilibrium Logic

摘要

We investigate an alternative language for equilibrium logic that is based on the concept of positive and negative contingency. Beyond these two con cepts our language has the modal operators of necessity and impossibility and the Boolean operators of conjunction and disjunction. Neither negation nor implica tion are available. Our language is just as expressive as the standard language of equilibrium logic (that is based on conjunction and intuitionistic implication).