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Aug 28, 2003, 8:40am

From Steve Gibson's Inbox:

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How to Prove It
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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 generalisation 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 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 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.

Aug 28, 2003, 3:27pm

That would be a nice thing to go up in a maths classroom! :D

- Mark

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Aug 28, 2003, 6:52pm

This, Gibson fellow... has a lot of time on his hands.

-Joe

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Aug 28, 2003, 7:31pm

[View Quote] He probably has and he invest it in te internet community generously. I don't know why an email in the inbox indicate it but if you wish .....

OTOH - It is a good idea to visit http://www.grc.com anyway.

--
Andras
"It's MY computer" (tm Steve Gibson)

Aug 29, 2003, 12:41am

agreed,..... Gibson rulez :)


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Aug 30, 2003, 3:21pm

Hey, I'd have a lot of time on my hands if I had two T1 lines, multiple
routers, made software so easy to use that it doesn't need a help file,
and was a security expert to boot. ;) He also used to be a writer for
many, many years. Computers are his passion.

Builderz
http://www.3dhost.net

[View Quote]

Aug 30, 2003, 4:52pm

Does he mention proof by "while you twits were arguing
around the blackboard I built one and it works"?

:-)

PS - "it's now patented"!

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Aug 30, 2003, 9:10pm

.... it seems it is.

-Joe

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