Metamath Proof Explorer


Table of Contents - 20.46.14. Formal methods "surprises"

Prove that some formal expressions using classical logic have meanings that might not be obvious to some lay readers. I find these are common mistakes and are worth pointing out to new people. In particular we prove alimp-surprise, empty-surprise, and eximp-surprise.

  1. alimp-surprise
  2. alimp-no-surprise
  3. empty-surprise
  4. empty-surprise2
  5. eximp-surprise
  6. eximp-surprise2