modal logic
formal logic able to express concepts such as necessity, possibility, provability, obligation, knowledge etc.
dynamic logic
extension of modal logic
classical modal logic
modal logic containing the duality axiom schema ◊A↔¬◻¬A as well as the deduction rule A↔B ⊢ ◻A↔◻B
relevance logic
mathematical logic system that imposes certain restrictions on implication
epistemic modal logic
subfield of modal logic that is concerned with reasoning about knowledge