Remark: Deciding if a proof of a proposition exists* up to a certain length n is NP-COMPLETE. Deciding if a proof exists at all - which is the Entscheidungsprob

Remark: Deciding if a proof of a proposition exists* up to a certain length n is NP-COMPLETE. Deciding if a proof exists at all - which is the Entscheidungsproblem - is semi-decidable. So the parent wasn't entirely wrong. * - In Peano arithmetic, let's say