Re: What is the Result from Invoking this Halt Function?

From: David C. Ullrich (ullrich_at_math.okstate.edu)
Date: 08/21/04 

Date: Sat, 21 Aug 2004 05:42:06 -0500

On Sat, 21 Aug 2004 03:11:41 GMT, "Peter Olcott"
<olcott@worldnet.att.net> wrote:

>
>"David C. Ullrich" <ullrich@math.okstate.edu> wrote in message news:2imbi0p20o42ubh20bosrciekr2sver8ha@4ax.com...
>> On Fri, 20 Aug 2004 02:30:41 GMT, "Peter Olcott"
>> <olcott@worldnet.att.net> wrote:
>
>> >> > uh, right. i'll let somone who knows C decide whether this
>> >> > works [the fact that there's only a single loop makes me
>> >> > doubt it...] the point was to make it as simple to
>> >> > understand as possible.
>> >>
>> >> It's not quite right but it's close.
>> >>
>> >> int main() { int i,j,k; for(i=j=k=1;--j||k;k=j?i%j?k:k-j:(j=i+=2)); return 0; }
>> >>
>> >> The main problem with C is that 'int' is a fixed precision, which
>> >> means it may not solve the desired problem that it's coded for.
>> >> However, the question is still a mildly interesting one;
>> >> all I've done is reframed it properly, and now I can compile it. :-)
>> >>
>> >> >
>> >> > does it halt or not?
>> >
>> >This one would not halt.
>>
>> ah. how do you -know-? [hint: -proving- it doesn't halt gives
>> a solution to a very old problem that nobody knows how to solve.
>
>I know that it does not halt in this case, and the answer is very
>easy. I will let you think about it for awhile, and answer on your
>next reply, if you haven't yet figured it out by then.

i haven't figured it out. just like no other mathematician since
euclid has figured it out. so give us the easy answer already.

>> so you should really explain how you know it doesn't halt, lest
>> people assume that you're just guessing. note that since a
>> correct answer is going to make you famous, nobody is going to
>> believe any weaseling about how you'd just rather not say...]
>

************************

David C. Ullrich

sorry about the inelegant formatting - typing
one-handed for a few weeks...

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