3 ms·

> "If X is greater than 10, X is greater than 20" theorems I think you meant in the opposite order, i.e.: "If X is greater than 20, then X is greater than 10"

• jerf 3y ago
  Whoops, yes, thanks, fixed. One of those things I edited one too many times and didn't catch in the end.
• Koshkin 3y ago
  > > "If X is greater than 10, X is greater than 20" theorems I think I have seen theorems of that sort. (Can't think of a specific example right now.)
  • someplaceguy 3y ago
    A theorem like that isn't provable (unless you're using some kind of nonstandard arithmetic). You could only prove it if you add something else, e.g. a precondition saying that X = 30.
    • Koshkin 3y ago
      Right, if it can be asserted based on some independent assumptions that a positive X must be at least 30, then from those assumptions and X > 10 it would follow that X > 20.
      • carnitine 3y ago
        It also just follows from X being >= 30.