The basic structure of a proof is just a series of statements, each one being either:

  • An assumption, or
  • A conclusion, clearly following from an assumption or previously proved result.

What a proof should be

A well written proof will flow; the reader should be taken directly and inevitably to the desired conclusion, without any irrelevant details.

Each step (statement) should be clear or at least clearly justified.

Testing if a sentence belongs to a proof

Apply this test to every sentence of a proof: Is it clearly

  • a. an assumption, or
  • b. a justified conclusion?

If the test fails, maybe it doesn’t belong in the proof.