After getting insulted by Random Poster for rambling on in a proof, I decided to post this list of proof techniques. Some of you may have seen this before; Bob will accuse me of violating a copyright. But I thought most members would like this.
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Proof Techniques
Proof by Contradiction: "This theorem contradicts a wellknown result due to Isaac Newton."
Proof by Metacontradiction: "We prove that a proof exists. To do so, assume that there is no proof..."
Proof by Deferral: "We'll prove this next week."
Proof by Cyclic Deferral: "As we proved last week..."
Proof by Indefinite Deferral: "As I said last week, we'll prove this next week."
Proof by Intimidation: "As any fool can see, the proof is obviously trivial."
Proof by Deferred Intimidation: "As any fool can see, the proof is obviously trivial." "Sorry, Professor, are you sure?" Goes away for half an hour. Comes back. "Yes."
Proof by Handwaving: "Selfexplanatory." Most effective in seminars and conference talks.
Proof by Vigorous Handwaving: More tiring, but more effective.
Proof by Overoptimistic Citation: "As Pythagoras proved, two cubes never add up to a cube."
Proof by Personal Conviction: "It is my profound belief that the quaternionic pseudoMandelbrot set is locally disconnected."
Proof by Lack of Imagination: "I can't think of any reason why it's false, so it must be true."
Proof by Forward Reference: "My proof that the quaternionic pseudoMandelbrot set is locally disconnected will appear in a forthcoming paper." Often not as forthcoming as it seemed when the reference was made.
Proof by Example: "We prove the case n = 2 and then let 2 = n."
Proof by Omission: "The other 142 cases are analogous."
Proof by Outsourcing: "Details are left to the reader."
Statement by Outsourcing: "Formulation of the correct theorem is left to the reader."
Proof by Unreadable Notation: "If you work through the next 500 pages of incredibly dense formulas in six alphabets, you'll see why it has to be true."
Proof by Authority: "I saw Milnor in the cafeteria and he said he thought it's probably locally disconnected."
Proof by Personal Communication: "The quaternionic pseudoMandelbrot set is locally disconnected (Milnor, personal communication)."
Proof by Vague Authority: "The quaternionic pseudoMandelbrot set is wellknown to be locally disconnected."
Proof by Provocative Wager: "If the quaternionic pseudoMandelbrot set is not locally disconnected, I'll jump off London Bridge wearing a gorilla suit."
Proof by Erudite Allusion: "Local connectivity of the quaternionic pseudoMandelbrot set follows by adapting the methods of Cheesburger and Fries to noncompact infinitedimensional quasimanifolds over skew fields of characteristic greater than 11."
Proof by Reduction to the Wrong Problem: "To see that the quaternionic pseudoMandelbrot set is locally disconnected, we reduce it to Pythagoras's Theorem."
Proof by Inaccessible Reference: "A proof that the quaternionic pseudoMandelbrot set is locally disconnected can be easily derived from Pzkrzwcziewszczii's privately printed memoir bound into volume 1 1/2 of the printer's proofs of the 1831 Proceedings of the South Liechtenstein Ladies' Knitting Circle before the entire print run was pulped."
