Bisimulations 2 Boolean functions 2 Coinduction 2 Conjunctive normal forms 2 Hybrid logic 2 Hybrid logics 2 Modal depth 2 Modal formulas 2 Modal language 2 Modal logic 2 Modal logics 2 Normal form 2 Normal forms 2 Polynomial approximation 2 Polynomial-time 2 Propositional logic 2 Satisfiability 2