Practice question · Select all that apply
Which statements about entailment are correct?
Hints
- Three are standard results; one reverses a one-way entailment.
- A conjunction gives you each conjunct, but a single conjunct does not give you the conjunction.
Show the answer
- A. P and Q entails P
- B. Logical equivalence is entailment in both directions
- C. Entailment can hold in one direction only
Why
A conjunction entails each conjunct, but not conversely, knowing tells you nothing about . Equivalence is exactly mutual entailment, which is why it is the stronger relation.
Practise Tautology, Entailment and Consistency
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