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Single Idea 14971

[from 'Modal Logic' by Max J. Cresswell, in 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

Source

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

Book Reference

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