5 ms·

Basically just https://en.wikipedia.org/wiki/Proof_by_contradiction https://en.wikipedia.org/wiki/Proof_by_contradiction

• EGreg 9y ago
  I mean about the converse. Why does it work?
  • qntty 9y ago
    [Proof by contradiction doesn't have anything to do with the converse of a statement as andrewaylett incorrectly stated and EGreg is being a little bit difficult here.]