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.”

http://jwilson.coe.uga.edu/EMT668/EMAT6680.F99/Challen/proof/proof.html

As a mathematician you would find this funny… Only if all math are like this…

http://en.wikipedia.org/wiki/Invalid_proof

Some of these were pretty funny too…