Re: Yet another Attempt at Disproving the Halting Problem

From: David C. Ullrich (ullrich_at_math.okstate.edu)
Date: 07/31/04 

Date: Sat, 31 Jul 2004 06:50:05 -0500

On Fri, 30 Jul 2004 21:20:35 GMT, "Peter Olcott"
<olcott@worldnet.att.net> wrote:

>
>"Chris Menzel" <cmenzel@remove-this.tamu.edu> wrote in message news:slrncgfgvd.5rf.cmenzel@philebus.tamu.edu...
>> On Wed, 28 Jul 2004 12:07:38 GMT, Peter Olcott <olcott@worldnet.att.net> said:
>> >
>> > "Chris Menzel" <cmenzel@remove-this.tamu.edu> wrote in message
>> > news:slrncge8q6.5rf.cmenzel@philebus.tamu.edu...
>> >> On Tue, 27 Jul 2004 22:58:47 GMT, Peter Olcott
>> >> <olcott@worldnet.att.net> said:
>> > But within math the abstraction and the what it being presented are one
>> > and the same thing. With computer science there are two apsects:
>> > (1) The algorithm
>> > (2) A physical implemenatation on a real machine.
>> > Because of this what can be proven from a math point of view,
>> > might not apply on the comp sci side. What is proven for the
>> > algorithm might not carry over to physical hardware.
>>
>> This is, well, just stunningly clueless.
>
>Now I have the concrete example that I was intuitively thinking of when I
>said this. One thing that could make a big difference in the outcome of
>evaluating a line-of-reasoning is the possibility of a separate memory space.
>This is not the sort of thing that the purely math way of looking at the problem
>even has a representation for.

ah, a post that can easily be answered one-handed through the wonders
of cut&paste:

This is, well, just stunningly clueless.

> Math looks at the problem at a higher level
>of abstraction, and abstracts out these possibly crucial details. The example
>below makes my point.
>
>There are two different memory spaces for two different copies of the exact
>same bool WillHalt() function. In the same way that the void WillHalt() function
>makes it impossible for LoopIfHalts() to use its result to make the Halting
>Problem unsolvable, the separate memory space accomplishes the same result.
>
>//
>// All of the functions are assumed to be standard C++
>//
>void LoopIfHalts(string ProgramSourceFile, string InputData)
>{
> if (WillHalt01(ProgramSourceFile, InputData))
> while (true)
> ;
> else // to make it easier for people who don't know C++
> return;
>}
>
>bool WillHalt02(LoopIfHalts, LoopIfHalts)
>
>This second copy of WillHalt() can determine that LoopIfHalts() will halt.
>

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

David C. Ullrich

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

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