Tony Morris

@dibblego I should have said 'phrase' not 'word'. In any case, I submit: Can you answer, "Does the boiling point of a triangle exist?"

@clhodapp No I cannot. I don't even ask the question, just like you don't.

@dibblego At least you're consistent. This would indicate that you can never answer "Does X exist?" with "no". This is quite a position.

@clhodapp Is the perimeter of a triangle ABC greater or less than 100cm? This is answerable.

@dibblego Ah, but see, neither of these are "Does X exist?" questions. Can you generate one where X is not bottom and the answer is "no"?

@clhodapp All questions are reducible to this decision problem.

@dibblego Perhaps. "Does there exist a number X, such that X is greater or less than 100cm and X is the perimeter of triangle ABC".

@dibblego Except, if not, X does not exist, so we can't answer the question.