Classical modal logic: Difference between revisions

Revision as of 12:05, 10 November 2012

Revision as of 14:01, 28 February 2013

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<math> A \equiv B \vdash \Diamond A\equiv\Diamond B.</math>

The weakest classical system is sometimes referred to as '''E''' and is [[normal modal logic|non-normal]]. Both [[algebraic semantics (mathematical logic)|algebraic]] and [[neighborhood semantics]] characterize familiar classical modal systems that are weaker than the weakest normal modal logic '''K'''.

Every [[regular modal logic]] is classical, and every [[normal modal logic]] is regular and hence classical.