Recent content by Logic1

Thank Ackbach! I made a typing error I think. I meant ¬(p→q)⟹(p∧¬q) of course. To apply the ∧-introduction, I need to get P and ¬Q. But I do not see yet which steps I can start with to make the →-elimination possible (it's clearly not applicable immediately).

The proposition ¬(P→Q) is equivalent to ¬P^Q Does someone maybe have an idea how you can prove (directly) ¬P^Q from ¬(P→Q) by means of natural deduction? I do not manage it. Thanks in advance!