Modal language Modal logic 4 Satisfiability 4 Automata theory 2 Biomineralization 2 Bisimulations 2 Boolean functions 2 Coinduction 2 Conjunctive normal forms 2 Data structures 2 Hybrid logic 2 Hybrid logics 2 Linguistics 2 Logical language 2 Modal depth 2 Modal formulas 2 Modal logics 2 Model checking 2 Model checking problem 2 Normal form 2 Normal forms 2 Polynomial approximation 2 Polynomial-time 2 Problem solving 2 Propositional logic 2 Relational Model 2 Satisfiability problems 2 Sublanguages 2