### Methods of Mathematical Proof
(Anonymous)

*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 constraint, I'll leave the proof to you."

*Proof by postponement*

"The proof for this is 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 mumbo-jumbo*

" (B Ì P ) , $ (C Î W )

*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 plagiarism*

"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*

(scribble, scribble) QED

*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 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 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 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 just have this gut feeling. . ."