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From: olcott <polcott333@gmail.com>
Newsgroups: comp.theory
Subject: Re: How to write a self-referencial TM?
Date: Fri, 16 May 2025 10:37:48 -0500
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On 5/16/2025 2:24 AM, Mikko wrote:
> On 2025-05-14 17:24:36 +0000, olcott said:
> 
>> On 5/14/2025 11:43 AM, wij wrote:
>>> On Wed, 2025-05-14 at 09:51 -0500, olcott wrote:
>>>> On 5/14/2025 12:13 AM, wij wrote:
>>>>> Q: Write a turing machine that performs D function (which calls 
>>>>> itself):
>>>>>
>>>>> void D() {
>>>>>   D();
>>>>> }
>>>>>
>>>>> Easy?
>>>>>
>>>>>
>>>>
>>>> That is not a TM.
>>>
>>> It is a C program that exists. Therefore, there must be a equivalent TM.
>>>
>>>> To make a TM that references itself the closest
>>>> thing is a UTM that simulates its own TM source-code.
>>>
>>> How does a UTM simulate its own TM source-code?
>>
>> You run a UTM that has its own source-code on its tape.
> 
> A UTM requires a translation to its input language. A source code cannot
> be used unless it happens to be written in the UTM's input language.
> 

The Turing Machine specification language
that is misnamed the Turing Machine description
language. It is not any mere description of some
of the details. It is a complete specification of
all of the details.

-- 
Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer