Modal logic - Mathematical logic, Deontic logic, Doxastic logic, Intensional logic, Interpretation (logic), Accessibility relation, Possible world, De dicto and de re, Description logic, Dynamic logic (modal logic), Epistemic logic, Hybrid logic, Interior algebra, Kripke semantics, Provability logic, Modal verb, S5 (modal logic), Classical modal logic, Regular modal logic, Modal operator, Temporal logic, Linear temporal logic, Multimodal logic, Modal companion, Saul KripkeDana Scott