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IV.6 Satisfiable and valid

Satisfiable and valid [Slide 124]

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

Example 37.  

  • 0 < 1 is a valid formula.
  • Formula A < B is satisfiable because MA < B(σ0) = tt where state σ0 is such that σ0(A) = 0 and σ0(B) = 1.







2018-02-25
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