more from Max J. Cresswell

Single Idea 14971

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

Full Idea

If a frame contains any dead end or blind world, then D is not valid on that frame, ...but D is valid on every serial frame.

Gist of Idea

D is valid on every serial frame, but not where there are dead ends


Max J. Cresswell (Modal Logic [2001], 7.1.1)

Book Reference

'Blackwell Guide to Philosophical Logic', ed/tr. Goble,Lou [Blackwell 2001], p.140