(heard it, chuckle)

( This is/was posted on someone's door, whence I copied it. I don't have the source handy )

HOW TO PROVE ITproof by example: The author gives only the case n = 2 and suggests that it contains most of the ideas of the general proof.

proof by intimidation: "Trivial."

proof by vigorous handwaving: Works well in a classroom or seminar setting.

proof by cumbersome notation: Best done with access to at least four alphabets and special symbols.

proof by exhaustion: An issue or two of a journal devoted to your proof is useful.

proof by omission: "The reader may easily supply the details" "The other 253 cases are analogous" "..."

proof by obfuscation: A long plotless sequence of true and/or meaningless syntactically related statements.

proof by wishful citation: The author cites the negation, converse, or generalization of a theorem from the literature to support his claims.

proof by funding: How could three different government agencies be wrong?

proof by eminent authority: "I saw Karp in the elevator and he said it was probably NP- complete."

proof by personal communication: "Eight-dimensional colored cycle stripping is NP-complete [Karp, personal communication]."

proof by reduction to the wrong problem: "To see that infinite-dimensional colored cycle stripping is decidable, we reduce it to the halting problem."

proof by reference to inaccessible literature: The author cites a simple corollary of a theorem to be found in a privately circulated memoir of the Slovenian Philological Society, 1883.

proof by importance: A large body of useful consequences all follow from the proposition in question.

proof by accumulated evidence: Long and diligent search has not revealed a counterexample.

proof by cosmology: The negation of the proposition is unimaginable or meaningless. Popular for proofs of the existence of God.

proof by mutual reference: In reference A, Theorem 5 is said to follow from Theorem 3 in reference B, which is shown to follow from Corollary 6.2 in reference C, which is an easy consequence of Theorem 5 in reference A.

proof by metaproof: A method is given to construct the desired proof. The correctness of the method is proved by any of these techniques.

proof by picture: A more convincing form of proof by example. Combines well with proof by omission.

proof by vehement assertion: It is useful to have some kind of authority relation to the audience.

proof by ghost reference: Nothing even remotely resembling the cited theorem appears in the reference given.

proof by forward reference: Reference is usually to a forthcoming paper of the author, which is often not as forthcoming as at first.

proof by semantic shift: Some of the standard but inconvenient definitions are changed for the statement of the result.

proof by appeal to intuition: Cloud-shaped drawings frequently help here.