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II.7 Satisfiable and valid

Satisfiable and valid [Slide 40]

  • A propositional formula f is satisfiable if and only if there exists a state σ0 such that Mf(σ0) = tt.
  • A propositional formula f is valid if and only if for all states σ0, Mf(σ0) = tt.

Example 6.

  • true is a valid formula.
  • Proposition P Q is satisfiable because MP Q(σ0) = tt where state σ0 is such that σ0(P) = tt and σ0(Q) = tt.







2018-02-25
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