Re: Halting Problem: What Constitutes Pathological Input

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Sujet : Re: Halting Problem: What Constitutes Pathological Input
De : polcott333 (at) *nospam* gmail.com (olcott)
Groupes : comp.theory
Date : 05. May 2025, 19:09:36
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <vvaut0$vtiu$4@dont-email.me>
References : 1 2 3 4 5 6
User-Agent : Mozilla Thunderbird
On 5/5/2025 12:45 PM, dbush wrote:
On 5/5/2025 1:37 PM, olcott wrote:
On 5/5/2025 11:13 AM, Mr Flibble wrote:
On Mon, 05 May 2025 11:58:50 -0400, dbush wrote:
>
On 5/5/2025 11:51 AM, olcott wrote:
On 5/5/2025 10:17 AM, Mr Flibble wrote:
What constitutes halting problem pathological input:
>
Input that would cause infinite recursion when using a decider of the
simulating kind.
>
Such input forms a category error which results in the halting problem
being ill-formed as currently defined.
>
/Flibble
>
I prefer to look at it as a counter-example that refutes all of the
halting problem proofs.
>
Which start with the assumption that the following mapping is computable
and that (in this case) HHH computes it:
>
>
Given any algorithm (i.e. a fixed immutable sequence of instructions) X
described as <X> with input Y:
>
A solution to the halting problem is an algorithm H that computes the
following mapping:
>
(<X>,Y) maps to 1 if and only if X(Y) halts when executed directly
(<X>,Y) maps to 0 if and only if X(Y) does not halt when executed
directly
>
>
>
int DD()
{
    int Halt_Status = HHH(DD);
    if (Halt_Status)
      HERE: goto HERE;
    return Halt_Status;
}
>
https://github.com/plolcott/x86utm
>
The x86utm operating system includes fully operational HHH and DD.
https://github.com/plolcott/x86utm/blob/master/Halt7.c
>
When HHH computes the mapping from *its input* to the behavior of DD
emulated by HHH this includes HHH emulating itself emulating DD. This
matches the infinite recursion behavior pattern.
>
Thus the Halting Problem's "impossible" input is correctly determined
to be non-halting.
>
>
>
Which is a contradiction.  Therefore the assumption that the above
mapping is computable is proven false, as Linz and others have proved
and as you have *explicitly* agreed is correct.
>
The category (type) error manifests in all extant halting problem proofs
including Linz.  It is impossible to prove something which is ill-formed
in the first place.
>
/Flibble
>
The above example is category error because it asks
HHH(DD) to report on the direct execution of DD() and
the input to HHH specifies a different sequence of steps.
>
 In other words, you're demonstrating that you don't understand proof by contradiction, a concept taught to and understood by high school students more than 50 years your junior.
 
Self-contradiction is semantically ill-formed and has
nothing to do with proof by contradiction.
--
Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer

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