Logic 2

Question 1

Semantic Entailment (1)

Answer 1

1. φ1,…,φn |= ψ, if:

Each valuation that makes φ1, . . . , φn true, also makes ψ true.

Question 2

Counterexample (1)

Answer 2

1. φ1,…,φn true, but not ψ.