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 may 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 its
true."
 Proof by Convenience: "It would be very nice if
it were true, so ..."
 Proof by Necessity: "It had better be true or the
whole 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 constraint, I'll leave the proof to you."
 Proof by Postponement: "The proof for this is so
long and arduous, so it is given in the
appendix."
 Proof by Accident: "Hey, what have we here?"
 Proof by Insignificance: "Who really cares
anyway?"
 Proof by MumboJumbo: " For any epsilon> 0
there exists a corresponding delta > 0 s.t.
f(x)L < epsilon whenever xa < delta"
 Proof by Profanity: (example omitted)
 Proof by Definition: "We'll define it to be
true."
 Proof by Tautology: "It's true because it's
true."
 Proof by Plagiarism: "As we see on page 238 ..."
 Proof by Lost Reference: "I know I saw this
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: " ¥ ª Ð
Þ þæ"
 Proof by Logic: "If it is on the problem sheet,
then 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 just the
same as the last."
 Proof by Divine Word: "And the Lord said, 'Let
it be true,' and it came to pass."
 Proof by Stubbornness: "I don't care what you
say! It is true!"
 Proof by Simplification: "This proof reduces 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 t approaches infinity.
 Proof by Design: "If it's not true in today's
math, invent a new system in which it is."
 Proof by Intuition: "I just have this gut feeling
..."
 Proof by Authority: "Well, Bill Gates says it's
true, so it must be."
 Proof by Vigorous Assertion: "And I REALLY MEAN THAT!"
 Proof by A.F.K.T. Theorem: "Any Fool Knows That!"
 Proof by vigorous handwaving: Works well in a classroom.
 Proof by seduction: "Convince yourself that this is true!"
 Proof by accumulated evidence: "Long and diligent search has not
revealed a counterexample."
 Proof by Divine Intervention: "Then a miracle
occurs ..."
