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From: immibis <news@immibis.com>
Newsgroups: comp.theory,sci.logic
Subject: Re: We finally know exactly how H1(D,D) derives a different result
 than H(D,D)
Date: Fri, 8 Mar 2024 17:11:49 +0100
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On 8/03/24 04:31, Richard Damon wrote:
> On 3/7/24 6:16 PM, immibis wrote:
>> On 8/03/24 03:06, André G. Isaak wrote:
>>> On 2024-03-07 16:02, olcott wrote:
>>>
>>>> That Olcott machines always know their own TMD is unconventional.
>>>>
>>>> That their own TMD is correctly construed as an additional input
>>>> to their computation (whenever they don't ignore it) does provide
>>>> the reason why Ĥ.H ⟨Ĥ⟩ ⟨Ĥ⟩ <Ĥ> and H ⟨Ĥ⟩ ⟨Ĥ⟩ <H> can compute different
>>>> results and still be computations.
>>>
>>> It's also the reason why you approach is fundamentally flawed. 
>>> Putting aside the question of whether your proposal is workable (or 
>>> even sane), if your 'Olcott Machines' automatically supply the 
>>> machines they emulate with a copy of their own machine descriptions, 
>>> then you are no longer working on the halting problem.
>>>
>>> The halting problem asks, is it possible to construct a TM X that, 
>>> given a description of a second TM Y and an input string Z *and* 
>>> *only* *that* *input* *to* *work* *with*, is it possible for X to 
>>> determine whether Y applied to Z halts.
>>>
>>> Asking whether it is possible to construct a TM X which, given a 
>>> description of a second TM Y, and input string Z, *and* a description 
>>> X, can X determine whether Y applied to Z halts, is an *entirely* 
>>> different question.
>>>
>>> The answer to these two questions may well be entirely different, and 
>>> the answer to the second question tells us absolutely nothing about 
>>> the answer to the first, which is the only thing the halting problem 
>>> is concerned with.
>>>
>>> André
>>>
>>
>> It turns out that they are the same answer, since a machine which 
>> doesn't need its own description can ignore it, and a machine which 
>> does need its own description can be modified to include the 
>> description it needs (which won't be "its own" description any more, 
>> but it's impossible that it would need to be). Olcott is just grasping 
>> at straws to explain why obvious facts are false.
> 
> The problem is that a Turing Machine doesn't have *A* description, but 
> an infinte number of them. It can assume one of them, but that is 
> worthless for trying to find a copy of itself in the input, because it 
> has no idea which of the infinte variations that will be.

that isn't the problem