This list has been compiled by Dana Angluin and was originally published in SIGACT News, Winter-Spring, 1983, Volume 15 #1.

**Proof 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 claim.**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 coloured cycle stripping is NP-complete (Karp, personal communication).”**Proof by reduction to the wrong problem**“To see that infinite-dimensional coloured 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 accumulation of 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 by the author.**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.

The following methods have been used successfully and have been consequently submitted by fellow readers and members.

**Proof by lack of imagination**How could a life form not be carbon based?