Single Idea 14970

[catalogued under 4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / b. System K]

Full Idea

Normal propositional modal logics derive from the minimal system K: wffs of PC are axioms; □(p⊃q)⊃(□p⊃□q); uniform substitution; modus ponens; necessitation (α→□α).

Gist of Idea

Normal system K has five axioms and rules

Source

Max J. Cresswell (Modal Logic [2001], 7.1)

Book Reference

'Blackwell Guide to Philosophical Logic', ed/tr. Goble,Lou [Blackwell 2001], p.137

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