Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: Mike Terry <news.dead.person.stones@darjeeling.plus.com>
Newsgroups: comp.theory
Subject: Re: Why Peter Olcott is incorrect
Date: Sun, 18 May 2025 02:06:43 +0100
Organization: A noiseless patient Spider
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On 18/05/2025 01:11, Mr Flibble wrote:
> Hi!
> 
> In the case of pathological input, Peter's SHD only needs to report a
> correct halting result *as if* the simulation was run to completion:

Right.  If the simulation is run to completion, that's like a UTM simulating the input, and 
equivalent to asking whether the input halts.  This is the case for all inputs, not just 
"pathological" ones, whatever they are exactly.

PO's DD() calls an "embedded HHH" which aborts its simulation.  If that DD is simulated to 
completion it halts, so that is what his SHD needs to report.  PO has verified this directly, and 
has published the traces showing DD halting when simulated to completion.

> whether we abort, or continue until we run out of stack space makes no
> difference: we are detecting INFINITE recursion which can be viewed as non-
> halting.

Eh?  PO does have a couple of SHDs that simulate his DD to completion, and they all show DD halting! 
  There's no infinite recursion, only some level of finite recursive simulation.

PO gets confused, because his SHD HHH simply /doesn't/ simulate DD to completion.  It aborts, and 
then decides non-halting.  That's the reverse of what you said in the first paragraph.  So your 
thread title is misleading - PO is actually *incorrect*.  I've corrected the title to avoid confusion.


Mike.