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 -> r), q => p -> r
⇒ conj-intro, initial=TList [TCon logic1.implies [TVar "p",TCon logic1.implies [TVar "q",TVar "r"]],TVar "q"](p -> (q -> r)) /\ q => p -> r
⇒ logic.propositional.defimpl(~p || (q -> r)) /\ q => p -> r
⇒ logic.propositional.defimpl(~p || ~q || r) /\ q => p -> r
⇒ logic.propositional.defimpl(~p || ~q || r) /\ q => ~p || r
⇒ fakeabsorption(~p || r) /\ q => ~p || r
⇒ conj-elim~p || r => ~p || r