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From: Richard Damon <richard@damon-family.org>
Newsgroups: comp.theory
Subject: Re: How the requirements that Professor Sipser agreed to are exactly
 met --- WDH
Date: Sat, 17 May 2025 11:09:03 -0400
Organization: i2pn2 (i2pn.org)
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On 5/17/25 10:27 AM, Mike Terry wrote:
> On 17/05/2025 09:55, Mikko wrote:
>> On 2025-05-16 14:47:39 +0000, olcott said:
>>
>>> On 5/16/2025 4:26 AM, Mikko wrote:
>>>> On 2025-05-15 00:36:21 +0000, Mike Terry said:
>>>>
>>>>> On 14/05/2025 22:31, Keith Thompson wrote:
>>>>>> olcott <polcott333@gmail.com> writes:
>>>>>>> On 5/14/2025 3:51 PM, dbush wrote:
>>>>>>>> On 5/14/2025 11:45 AM, olcott wrote:
>>>>>>>>> On 5/14/2025 6:20 AM, Richard Damon wrote:
>>>>>>>>>>
>>>>>>>>>> And since the DD that HHH is simulating WILL HALT when fully
>>>>>>>>>> simulated (an action that HHH doesn't do)
>>>>>>>>>
>>>>>>>>> *NOT IN THE ACTUAL SPEC*
>>>>>>>>> <MIT Professor Sipser agreed to ONLY these verbatim words 
>>>>>>>>> 10/13/2022>
>>>>>>>>>      If simulating halt decider H correctly simulates its
>>>>>>>>>      input D until H correctly determines that its simulated D
>>>>>>>>>      would never stop running unless aborted then
>>>>>>>>>
>>>>>>>> That Sipser didn't agree what you think the above means:
>>>>>>>>
>>>>>>>
>>>>>>> If that was actually true then you could provide an
>>>>>>> alternative meaning for the exact words stated above.
>>>>>>>
>>>>>>> I keep challenging you to provide this alternative
>>>>>>> meaning and you dodge because you know that you are
>>>>>>> lying about there being any alternative meaning
>>>>>>> FOR THE EXACT WORDS LISTED ABOVE.
>>>>>>
>>>>>> No alternative meaning is needed, just a correct interpretation of 
>>>>>> the
>>>>>> words (which appear to be incomplete).
>>>>>>
>>>>>> The quoted sentence is cut off, something that I suspect you didn't
>>>>>> notice.  Here's the full quotation from a previous article:
>>>>>>
>>>>>>>> <Sipser approved abstract>
>>>>>>>> MIT Professor Michael Sipser has agreed that the following verbatim
>>>>>>>> paragraph is correct (he has not agreed to anything else in this
>>>>>>>> paper):
>>>>>>>>
>>>>>>>> If simulating halt decider H correctly simulates its input D 
>>>>>>>> until H
>>>>>>>> correctly determines that its simulated D would never stop running
>>>>>>>> unless aborted then H can abort its simulation of D and correctly
>>>>>>>> report that D specifies a non-halting sequence of configurations.
>>>>>>>> </Sipser approved abstract>
>>>>>>
>>>>>> **If** H correctly simulates its input in the manner you claim,
>>>>>> **then** H can correctly report the halting status of D.  (That's a
>>>>>> paraphrase that probably doesn't capture the full meaning; the full
>>>>>> **quotation is above.)
>>>>>>
>>>>>> To put it another way, If H correctly simulated its input in
>>>>>> the manner you claim, then H could correctly report the halting
>>>>>> status of D.
>>>>>>
>>>>>> I'm not surprised that Sipser would agree to that.  The problem is
>>>>>> that it's a conditional statement whose premise is impossible.
>>>>>>
>>>>>> If an equilateral triangle had four sides, then each of its four
>>>>>> vertices would be 90 degrees.  That doesn't actually mean that
>>>>>> there exists an equilateral triangle with four 90-degree vertices,
>>>>>> and in fact no such triangle exists.  Similarly, *if* a general
>>>>>> halt decider existed, then there are a lot of things we could say
>>>>>> about it -- but no general halt decider can exist.
>>>>>>
>>>>>> I'm not quite 100% confident in my reasoning here.  I invite any
>>>>>> actual experts in computational theory (not you, PO) to criticize
>>>>>> what I've written.
>>>>>
>>>>> I doubt that Sipser would be using your interpretation, relying on 
>>>>> a false premise as a clever kind of logical loop-hole to basically 
>>>>> fob someone off.
>>>>
>>>> The details of H are not known to Sipser, so he can't know whether a
>>>> premise is false. It is possible that some simulating partial decider
>>>> correctly simulates a part of the behaviour of some D and correctly
>>>> determines that the unsimulated part of the behaviour never halts;
>>>> for example, if the unsimulated part is a trivial eternal loop. That
>>>> one premise is false about HHH with DDD is a part of what was asked.
>>>
>>> Mike explains all of the details of exactly how a
>>> correct Simulating Halt Decider is derived from
>>> the exact meaning of the words that professor Sipser
>>> agreed to IN THE PART THAT YOU IGNORED
>>
>> No, he does not. He does not even believe that it is possible to derive
>> a correct Simulating Halt Decider form the exact meaning of any words.
>>
> 
> That's correct.
> 
> We could build a correct /partial/ SHD though, which I explained.  The 
> idea behind an PSHD is ok, and a class of HP inputs could be correctly 
> decided with a PSHD.  Obviously a PSHD H could not decide its 
> corresponding H^ input, as the Linz HP proof implies.  Since PO's HHH / 
> does/ decide its corresponding DD (incorrectly), it is not a PSHD, since 
> PSHDs are not allowed to decide incorrectly.  [A correctly coded PSHD 
> HHH would never halt when given its (HHH^,HHH^) input.
> 
> PO's problem is that he misunderstands the entire context of Sipser's 
> words.  Sipser's words concern how a PSHD H could decide some FIXED 
> INPUT D it has been given.  PO wants to interpret them as what happens 
> when H is modified, and D is also modified to reference the new H.  So 
> he's modifying what is supposed to be a fixed input half way through his 
> interpretation.  Sipser would be holding his head in his hands if he 
> knew (and cared) ... :)
> 
> 
> Mike.
> 

Yes, and in simpler words, PO doesn't understand the meaning of the 
words "Proggram" as they pertain here, as being a fully defined sequence 
of deterministic algorithmic steps that can be applied to an input.

As such, once defined it can not be changed. His hypothetical concept of 
"unless it aborted" is just a category error the way he is trying to 
define it, it is as silly as saying "unless 1 is equal to 2", as the 
program that was defined to abort can not be thought of as the same 
program and it not aborting.

We CAN hypothosize this input being given to a DIFFERENT program, one 
that doesn't abort but does fully correctly simulate the input, but the 
acknoledgement that it is a different program breaks his arguement that 
the code in the input should change.

This is why he gets stuck in a twisty maze of statements that are all 
not quite fully defined, as whem fully defined the path is clear, that 
he is just wrong.