__36 Methods of Mathematical Proof__
If the proof of a theorem is not immediately apparent, it may be
because you are trying the wrong approach. Below are some effective methods
of proof that might aim you in the right direction.

**Proof by obviousness:** "The proof is so clear that it need not be mentioned."
**Proof by general agreement:** "All in favor?..."
**Proof by imagination:** "Well, we'll pretend it's true..."
**Proof by convenience:** "It would be very nice if it were true, so..."
**Proof by necessity:** "It had better be true, or the entire structure of mathematics would crumble to the ground."
**Proof by plausibility:** "It sounds good, so it must be true."
**Proof by intimidation:** "Don't be stupid; of course it's true!"
**Proof by lack of sufficient time:** "Because of the time constrait, I'll leave the proof to you."
**Proof by postponement:** "The proof for this is long and arduous, so it is given to you in the appendix."
**Proof by accident:** "Hey, what have we here?!"
**Proof by insignificance:** "Who really cares anyway?"
**Proof by mumbo-jumbo:**
**Proof by profanity:** (example omitted)
**Proof by definition:** "We define it to be true."
**Proof by tautology:** "It's true because it's true."
**Proof by plagarism:** "As we see on page 289,..."
**Proof by lost reference:** "I know I saw it somewhere...."
**Proof by calculus:** "This proof requires calculus, so we'll skip it."
**Proof by terror:** When intimidation fails...
**Proof by lack of interest:** "Does anyone really want to see this?"
**Proof by illegibility:**
**Proof by logic:** "If it is on the problem sheet, it must be true!"
**Proof by majority rule:** Only to be used if general agreement is impossible.
**Proof by clever variable choice:** "Let A be the number such that this proof works..."
**Proof by tessellation:** "This proof is the same as the last."
**Proof by divine word:** "...And the Lord said, 'Let it be true,' and it was true."
**Proof by stubbornness:** "I don't care what you say- it is true."
**Proof by simplification:** "This proof reduced to the statement 1 + 1 = 2."
**Proof by hasty generalization:** "Well, it works for 17, so it works for all reals."
**Proof by deception:** "Now everyone turn their backs..."
**Proof by supplication:** "Oh please, let it be true."
**Proof by poor analogy:** "Well, it's just like..."
**Proof by avoidance:** Limit of proof by postponement as it approaches infinity
**Proof by design:** If it's not true in today's math, invent a new system in which it is.
**Proof by authority:** "Well, Don Knuth says it's true, so it must be!"
**Proof by intuition:** "I have this gut feeling."

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