Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: "Fred. Zwarts" <F.Zwarts@HetNet.nl>
Newsgroups: comp.theory
Subject: Re: Turing Machine computable functions apply finite string
 transformations to inputs
Date: Wed, 7 May 2025 12:11:57 +0200
Organization: A noiseless patient Spider
Lines: 116
Message-ID: <vvfble$ubvt$1@dont-email.me>
References: <TuuNP.2706011$nb1.2053729@fx01.ams4>
 <87cyd5182l.fsf@nosuchdomain.example.com> <vu6lnf$39fls$2@dont-email.me>
 <vugddv$b21g$2@dont-email.me> <vui4uf$20dpc$1@dont-email.me>
 <vuivtb$2lf64$3@dont-email.me> <vungtl$2v2kr$1@dont-email.me>
 <vuoaac$3jn5n$5@dont-email.me> <vuq81v$1hjka$1@dont-email.me>
 <vutefq$gmbi$3@dont-email.me> <vv22hs$puqs$1@dont-email.me>
 <vv89ll$2erlq$4@dont-email.me> <vv8en2$2kjgk$3@dont-email.me>
 <vv8ot8$2ub3p$1@dont-email.me> <vv8pqu$2ut5q$1@dont-email.me>
 <5YRRP.109778$_Npd.21893@fx01.ams4> <vv9142$35pgh$1@dont-email.me>
 <018f45d4807ba7b0092370889153d51d798e112e@i2pn2.org>
 <vvbsb1$1us1f$4@dont-email.me>
 <41f4ae4e8e8e5342aa358b440411de773d08c581@i2pn2.org>
 <vvdh7t$3cbpq$4@dont-email.me> <vvdmag$3huo6$1@dont-email.me>
 <vvdmsq$3k2gc$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Wed, 07 May 2025 12:11:58 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="1f8f63a6b9b5f3b438700d1281f1281f";
	logging-data="995325"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19HpmQ1lzlrgV2pDNAnKuFf"
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:QYiGAdaWIHlPTNIycrsaRB0FMx8=
Content-Language: nl, en-GB
In-Reply-To: <vvdmsq$3k2gc$1@dont-email.me>

Op 06.mei.2025 om 21:11 schreef olcott:
> On 5/6/2025 2:01 PM, Fred. Zwarts wrote:
>> Op 06.mei.2025 om 19:34 schreef olcott:
>>> On 5/6/2025 6:29 AM, Richard Damon wrote:
>>>> On 5/5/25 10:32 PM, olcott wrote:
>>>>> On 5/5/2025 8:19 PM, Richard Damon wrote:
>>>>>> On 5/4/25 8:35 PM, olcott wrote:
>>>>>>> On 5/4/2025 5:34 PM, Mr Flibble wrote:
>>>>>>>> On Sun, 04 May 2025 23:30:54 +0100, Richard Heathfield wrote:
>>>>>>>>
>>>>>>>>> On 04/05/2025 23:15, olcott wrote:
>>>>>>>>>> On 5/4/2025 2:21 PM, Richard Heathfield wrote:
>>>>>>>>>>> On 04/05/2025 18:55, olcott wrote:
>>>>>>>>>>>> Changing my words then rebutting these changed words is 
>>>>>>>>>>>> dishonest.
>>>>>>>>>>>>
>>>>>>>>>>>> Functions computed by Turing Machines require INPUTS and 
>>>>>>>>>>>> produce
>>>>>>>>>>>> OUTPUTS DERIVED FROM THESE INPUTS.
>>>>>>>>>>>
>>>>>>>>>>> Counter-example: a Turing Machine can calculate pi without 
>>>>>>>>>>> any input
>>>>>>>>>>> whatsoever.
>>>>>>>>>>>
>>>>>>>>>>> As Mikko rightly said: a Turing machine does not need to 
>>>>>>>>>>> require an
>>>>>>>>>>> input.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>> IT IS NOT COMPUTING FUNCTION THEN
>>>>>>>>>
>>>>>>>>> Quoth Alan Turing:
>>>>>>>>>
>>>>>>>>> (viii) The limit of a computably convergent sequence is 
>>>>>>>>> computable.
>>>>>>>>>
>>>>>>>>>   From (viii) and TT— 4(1—i-|--i—...) we deduce that TT is 
>>>>>>>>> computable.
>>>>>>>>>
>>>>>>>>> No input required.
>>>>>>>>>
>>>>>>>>>> IT IS NOT COMPUTING FUNCTION THEN IT IS NOT COMPUTING FUNCTION 
>>>>>>>>>> THEN IT
>>>>>>>>>> IS NOT COMPUTING FUNCTION THEN
>>>>>>>>>>
>>>>>>>>>> Computable functions are the basic objects of study in 
>>>>>>>>>> computability
>>>>>>>>>> theory. Computable functions are the formalized analogue of the
>>>>>>>>>> intuitive notion of algorithms, in the sense that a function is
>>>>>>>>>> computable if there exists an algorithm that can do the job of 
>>>>>>>>>> the
>>>>>>>>>> function, i.e. given an input of the function domain it can 
>>>>>>>>>> return the
>>>>>>>>>> corresponding output. https://en.wikipedia.org/wiki/ 
>>>>>>>>>> Computable_function
>>>>>>>>>
>>>>>>>>> That's a very second-rate summary of computability. Turing was 
>>>>>>>>> far more
>>>>>>>>> interested in whether a computation was possible than whether 
>>>>>>>>> it needed
>>>>>>>>> inputs. Do most computations need inputs? Most useful ones that 
>>>>>>>>> we care
>>>>>>>>> about, sure. But all? By no means.
>>>>>>>>>
>>>>>>>>>> *Computer science is ONLY concerned with computable functions*
>>>>>>>>>
>>>>>>>>> Computer science is concerned with the Halting Problem.
>>>>>>>>> The Halting Problem is concerned with an incomputable function.
>>>>>>>>> Therefore computer science is concerned with at least one 
>>>>>>>>> incomputable
>>>>>>>>> function.
>>>>>>>>
>>>>>>>> The function is neither computable nor incomputable because 
>>>>>>>> there is no
>>>>>>>> function at all, just a category error.
>>>>>>>>
>>>>>>>> /Flibble
>>>>>>>
>>>>>>> You can look at it that way or you can look
>>>>>>> at it as simulating termination analyzer HHH(DD)
>>>>>>> does correctly determine that DD cannot possibly
>>>>>>> reach its own final state, thus is correctly
>>>>>>> rejected as non-halting.
>>>>>>>
>>>>>>
>>>>>> Except that isn't the question that is being asked.
>>>>>>
>>>>>> In fact, that question has a trivial answer, as we can make an H0 
>>>>>> that just aborts its emulation and returns 0 and it is correct by 
>>>>>> your definition, 
>>>>>
>>>>> No that is stupidly wrong as I have said at least 100 times recently.
>>>>> The termination analyzer must compute the mapping from the input
>>>>> on the basis of the behavior that this input actually specifies.
>>>>>
>>>>
>>>> Which *IS* by the DEFINITION of the problem, the behavior of the 
>>>> program the input represents when run.
>>>>
>>>
>>> That is not how it actually works.
>>> A function computed by a model of
>>> computation must compute the mapping
>>> FROM THE ACTUAL INPUT.
>> And the actual input specifies a halting program, 
> 
> Counter-factual
> That you don't have a clue about the x86 language
> is far less than no rebuttal at all.
No relevant information. No rebuttal.
The verifiable fact is that the direct execution uses exactly the same 
input, but HHH does not use the most important part of the input.
Halt7.c is included in the input and specifies a conditional abort, but 
the programmer of HHH made the mistake to let the program abort before 
it could see it. That does not change what is specified in the input, 
but is a bug in the program.