Exercise logic.propositional.consequence
Description
Prove that formula is a logical consequence of a set of formulas
Derivation
![](http://ideas.cs.uu.nl/images/external.png)
p -> q, p -> r => p -> (q /\ r)
⇒ conj-intro, initial=TList [TCon logic1.implies [TVar "p",TVar "q"],TCon logic1.implies [TVar "p",TVar "r"]](p -> q) /\ (p -> r) => p -> (q /\ r)
⇒ logic.propositional.defimpl(~p || q) /\ (p -> r) => p -> (q /\ r)
⇒ logic.propositional.defimpl(~p || q) /\ (~p || r) => p -> (q /\ r)
⇒ logic.propositional.defimpl(~p || q) /\ (~p || r) => ~p || (q /\ r)
⇒ logic.propositional.oroverand(~p || q) /\ (~p || r) => (~p || q) /\ (~p || r)