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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: Halting Problem: What Constitutes Pathological Input
Date: Wed, 7 May 2025 11:54:04 +0300
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On 2025-05-06 18:05:15 +0000, olcott said:

> That everyone here thinks that HHH can simply ignore
> the rules of the x86 language and jump over the "call"
> instruction to the "ret" instruction seems quite stupid
> to me.

The halting problem does not prohibit such skip so in that sense
it is OK.

However, in order to correctly determine whether DD halts
it may need to know whether the called HHH returns and what it
returns if it does.

When discussing the situation we need not consider what happens
during the execution of HHH. We do know that HHH returns if it
really is a halt decider or any other decider. We also know that
if it returns it either returns zero or someting else. The code
of DD shows that it halts if HHH(DD) returns zero and does not
halt fi HHH(DD) returns non-zero or does not return at all.

-- 
Mikko