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Re: Are the H(D) in main and the H(D) in D the same?

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On 2025-11-15, olcott <polcott333@gmail.com> wrote:
> On 11/15/2025 5:15 PM, Tristan Wibberley wrote:
>> On 15/11/2025 23:14, olcott wrote:
>>> On 11/15/2025 4:35 PM, Tristan Wibberley wrote:
>>>> On 15/11/2025 20:36, Kaz Kylheku wrote:
>>>>
>>>>> The underlying mathematics doesn't support that; the expression H(D)
>>>>> denotes exactly the same computation and result wherever it appears.
>>>>
>>>> Is this in the problem where C semantics are specified? There the
>>>> underlying mathematics supports it because of the semantics of the C
>>>> programming language.
>>>>
>>>
>>> D simulated by H specifies that H simulates
>>> D and then must simulate an instance of itself
>>> simulating an instance of D.
>>>
>>> D simulated by H1 does not specify that H1
>>> simulate itself at all.
>>>
>>> Any C programmer can instantly see this.
>> 
>> Thanks it doesn't help.
>> 
>
> C is essentially its own formal mathematical
> language with its own semantics thus what I
> just said applies to C as a formal language.

The problem, you idiot, is that same-named entities between
mathematics and C like "variable" and "function" do not correspond.

Yes, I know you like to assume that the same words refer to "isomorphic"
entities (another word you don't understand) but that simpy isn't so.

Even if we can build a formal model of C, that model cannot
turn a C function into a math function.

And, no, C is not formally specified. It is informally specified, in a
plain language description which leaves many details "unspecified",
"implementation-defined" and "undefined".  Every revision of the ISO C
standard has been the target of defect reports.

There are projects out there to do formal verification on C programs;
those have to construct their own formal model; you don't get one
from ISO C.

If you want certain functions in a C file to model math
functions (like functions from the theory of computation)
you have to tread very carefully.

You cannot pull bullshit like have to identical functions be
treated as different because one of them is called by
a certain function and the other isn't.

If you have two idnetical functions, you have to ensure that
everything in your system behaves as if they were just two
different /names/ for a single function.

Your functions cannot have any side effects, like reacting to
different values of a shared, static variable; they have to be pure.

-- 
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca

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Are the H(D) in main and the H(D) in D the same? wij <wyniijj5@gmail.com> - 2025-11-16 03:57 +0800
  Re: Are the H(D) in main and the H(D) in D the same? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-11-15 20:36 +0000
    Re: Are the H(D) in main and the H(D) in D the same? wij <wyniijj5@gmail.com> - 2025-11-16 05:11 +0800
      Re: Are the H(D) in main and the H(D) in D the same? olcott <polcott333@gmail.com> - 2025-11-15 15:40 -0600
        Re: Are the H(D) in main and the H(D) in D the same? wij <wyniijj5@gmail.com> - 2025-11-16 06:10 +0800
          Re: Are the H(D) in main and the H(D) in D the same? olcott <polcott333@gmail.com> - 2025-11-15 16:20 -0600
            Re: Are the H(D) in main and the H(D) in D the same? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-11-15 14:35 -0800
              Re: Are the H(D) in main and the H(D) in D the same? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-11-15 14:38 -0800
    Re: Are the H(D) in main and the H(D) in D the same? Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-11-15 22:35 +0000
      Re: Are the H(D) in main and the H(D) in D the same? olcott <polcott333@gmail.com> - 2025-11-15 17:14 -0600
        Re: Are the H(D) in main and the H(D) in D the same? Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-11-15 23:15 +0000
          Re: Are the H(D) in main and the H(D) in D the same? olcott <polcott333@gmail.com> - 2025-11-15 17:30 -0600
            Re: Are the H(D) in main and the H(D) in D the same? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-11-15 23:39 +0000
              Re: Are the H(D) in main and the H(D) in D the same? olcott <polcott333@gmail.com> - 2025-11-15 17:58 -0600
  Re: Are the H(D) in main and the H(D) in D the same? Mikko <mikko.levanto@iki.fi> - 2025-11-16 11:05 +0200

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