In article <36851139213559@[EMAIL PROTECTED]
>, Marcel Hendrix <mhx@[EMAIL PROTECTED]
>
wrote:
>Albert van der Horst <albert@[EMAIL PROTECTED]
> writes Re: OT: Errors in
Marcel's "Perfect Number code" examples?
>[..]
>> In article <18gtko9u67fij$.1bbn6thkqlgjh.dlg@[EMAIL PROTECTED]
>,
>> Coos Haak <chforth@[EMAIL PROTECTED]
> wrote:
>[..]
>>>> "The perfect number A can be characterized by a unique number n,
where A =
>>>> 2^n * (2^n-1 - 1). "
>>>
>>>2^(n - 1)*(2^n - 1)
>
>> The above is false.
>
>I do not say that it is a *necessary* condition.
That is silly. "being characterized by" is an idiomatic phrase
in mathematics. "Necessary condition" is another. If you want to
be understood, you better use applicable idiom in the correct way.
If you try to mend the phrase into
"Some perfect numbers A can be characterized by a unique number .."
my first reaction is
"so it is not a characterization at all."
(Same reaction, by the way, for
"The perfect number A can be characterized by a non-unique number ...)
>Anyway, if I had claimed that, it would have been close enough for
>engineering purposes: http://mathworld.wolfram.com/OddPerfectNumber.html
.
That would have amounted to claiming:
"there are no odd perfect numbers"
In a mathematical context that is not "almost true",
it is the title of a thesis that wins you a "summa *** laude".
This is one of the most famous unsettled problems in number theory.
Why would you resist changing your comment to the correct phrase?
" An even perfect number can be characterized by .."
>
>-marcel
>
Groetjes Albert
P.S.
If you talk mathematics, expect to be judged by mathematicians!
--
--
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- like all pyramid schemes -- ultimately falters.
albert@[EMAIL PROTECTED]
&=n http://home.hccnet.nl/a.w.m.van.der.horst
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