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From: Richard Damon <richard@damon-family.org>
Newsgroups: comp.theory,sci.logic
Subject: Re: Can an abort decider be defined that cannot be fooled by any
 pathological input?
Date: Tue, 26 Mar 2024 07:43:45 -0400
Organization: i2pn2 (i2pn.org)
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On 3/25/24 11:29 PM, olcott wrote:
> On 3/25/2024 10:01 PM, Richard Damon wrote:
>> On 3/25/24 10:53 PM, olcott wrote:
>>> On 3/25/2024 9:08 PM, Richard Damon wrote:
>>>> On 3/25/24 9:35 PM, olcott wrote:
>>>>> On 3/25/2024 8:30 PM, Richard Damon wrote:
>>>>>> On 3/25/24 9:12 PM, olcott wrote:
>>>>>>> On 3/25/2024 7:47 PM, Richard Damon wrote:
>>>>>>>> On 3/25/24 8:37 PM, olcott wrote:
>>>>>>>>> On 3/25/2024 7:22 PM, Richard Damon wrote:
>>>>>>>>>> On 3/25/24 8:11 PM, olcott wrote:
>>>>>>>>>>> On 3/25/2024 6:47 PM, Richard Damon wrote:
>>>>>>>>>>>> On 3/25/24 1:33 PM, olcott wrote:
>>>>>>>>>>>>> On 3/25/2024 11:16 AM, Fred. Zwarts wrote:
>>>>>>>>>>>>>> Op 25.mrt.2024 om 17:04 schreef olcott:
>>>>>>>>>>>>>>> On 3/25/2024 10:48 AM, Fred. Zwarts wrote:
>>>>>>>>>>>>>>>> Op 25.mrt.2024 om 16:17 schreef olcott:
>>>>>>>>>>>>>>>>> On 3/24/2024 3:51 AM, Fred. Zwarts wrote:
>>>>>>>>>>>>>>>>>> Op 24.mrt.2024 om 05:55 schreef olcott:
>>>>>>>>>>>>>>>>>>> Can an abort decider be defined that cannot be fooled 
>>>>>>>>>>>>>>>>>>> by any pathological input?
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> 01 int D(ptr x)  // ptr is pointer to int function
>>>>>>>>>>>>>>>>>>> 02 {
>>>>>>>>>>>>>>>>>>> 03   int Halt_Status = H(x, x);
>>>>>>>>>>>>>>>>>>> 04   if (Halt_Status)
>>>>>>>>>>>>>>>>>>> 05     HERE: goto HERE;
>>>>>>>>>>>>>>>>>>> 06   return Halt_Status;
>>>>>>>>>>>>>>>>>>> 07 }
>>>>>>>>>>>>>>>>>>> 08
>>>>>>>>>>>>>>>>>>> 09 void main()
>>>>>>>>>>>>>>>>>>> 10 {
>>>>>>>>>>>>>>>>>>> 11   H(D,D);
>>>>>>>>>>>>>>>>>>> 12 }
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Of all of the elements of the set of H(D,D) where H 
>>>>>>>>>>>>>>>>>>> simulates its
>>>>>>>>>>>>>>>>>>> input there are matched pairs of otherwise identical 
>>>>>>>>>>>>>>>>>>> elements that
>>>>>>>>>>>>>>>>>>> only differ by whether they abort their simulation or 
>>>>>>>>>>>>>>>>>>> not.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> The half of these that don't abort are incorrect 
>>>>>>>>>>>>>>>>>>> because all deciders
>>>>>>>>>>>>>>>>>>> must halt. This makes the other half correct about 
>>>>>>>>>>>>>>>>>>> the abort/no abort
>>>>>>>>>>>>>>>>>>> decision.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> No. The other, aborting, half is just wrong, because 
>>>>>>>>>>>>>>>>>> it aborts when it is not needed. So, the half that 
>>>>>>>>>>>>>>>>>> aborts is wrong and it may be argued that it is better 
>>>>>>>>>>>>>>>>>> to not abort something that halts on its own and that 
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> At least two software engineers with masters degrees in 
>>>>>>>>>>>>>>>>> computer science
>>>>>>>>>>>>>>>>> disagree.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Two is not many, considering that with Google for any 
>>>>>>>>>>>>>>>> invalid idea it is easy to find a several people with a 
>>>>>>>>>>>>>>>> master degree supporting it.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Exactly what are you software engineering skills?
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I have been professionally programming since 1986 in 
>>>>>>>>>>>>>>>> several languages. (Non professionally I started 
>>>>>>>>>>>>>>>> programming in 1975). Since about 1990 I programmed in C 
>>>>>>>>>>>>>>>> and since about 2000 in C++.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> I have been a professional C++ software engineer since 
>>>>>>>>>>>>>>>>> Y2K.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I'm sorry to hear that olcott has been so smart, but now 
>>>>>>>>>>>>>>>> he does not even sees what even a beginner sees.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Can D correctly simulated by H terminate normally?
>>>>>>>>>>>>>>> 01 int D(ptr x)  // ptr is pointer to int function
>>>>>>>>>>>>>>> 02 {
>>>>>>>>>>>>>>> 03   int Halt_Status = H(x, x);
>>>>>>>>>>>>>>> 04   if (Halt_Status)
>>>>>>>>>>>>>>> 05     HERE: goto HERE;
>>>>>>>>>>>>>>> 06   return Halt_Status;
>>>>>>>>>>>>>>> 07 }
>>>>>>>>>>>>>>> 08
>>>>>>>>>>>>>>> 09 void main()
>>>>>>>>>>>>>>> 10 {
>>>>>>>>>>>>>>> 11   H(D,D);
>>>>>>>>>>>>>>> 12 }
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> *Execution Trace*
>>>>>>>>>>>>>>> Line 11: main() invokes H(D,D);
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> *keeps repeating* (unless aborted)
>>>>>>>>>>>>>>> Line 03: simulated D(D) invokes simulated H(D,D) that 
>>>>>>>>>>>>>>> simulates D(D)
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Even a beginner sees that, if the H that aborts is chosen, 
>>>>>>>>>>>>>> simulated H(D,D) aborts and returns false (unless 
>>>>>>>>>>>>>> aborted). So simulated D halts (unless aborted).
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> I am estimating that you must be fibbing about your 
>>>>>>>>>>>>> programming skill.
>>>>>>>>>>>>> The D simulated by any implementation of H (that aborts or 
>>>>>>>>>>>>> does not
>>>>>>>>>>>>> abort its simulation) shown above cannot possibly reach its 
>>>>>>>>>>>>> own line 04
>>>>>>>>>>>>> also shown above.
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> But that isn't the question.
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> *That <is> the abort decision question*
>>>>>>>>>>
>>>>>>>>>> But you agreed that a correct abort decider oly NEEDS to abort 
>>>>>>>>>> its simulation if the correct simulation by a pure correct 
>>>>>>>>>> simulator of the input given to H (which doesn't change, so 
>>>>>>>>>> for this case, still calls that original H) will never reach a 
>>>>>>>>>> final state.
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>> The question is does that machine described by the input 
>>>>>>>>>>>> Halt when run, or, alternatively, does its correct 
>>>>>>>>>>>> simulation (not just by H) run forever (and thus needs to be 
>>>>>>>>>>>> aborted)?
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Since you know that H(D,D) must abort its simulation to 
>>>>>>>>>>> prevent its
>>>>>>>>>>> own infinite execution I don't understand why you would lie 
>>>>>>>>>>> about it.
>>>>>>>>>>
>>>>>>>>>> But an H that doesn't abort and an H that does abort are 
>>>>>>>>>> looking at different inputs "D", since you agree that the 
>>>>>>>>>> behavior of D changes based on the H that it is using.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Not at all. Of the infinite set of every possible 
>>>>>>>>> implementation of
>>>>>>>>> H where H(D,D) simulates its input everyone that chose to abort is
>>>>>>>>> necessarily correct.
>>>>>>>>>
>>>>>>>>> I don't understand why you persist in lying about this.
>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> I really want to get on to the next step and see if any input 
>>>>>>>>>>> can
>>>>>>>>>>> fool an abort decider into making the wrong abort decision.
>>>>>>>>>>
>>>>>>>>>> But you need to get this step right first.
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Perhaps you already know that you are not up to this challenge?
>>>>>>>>>>
>>>>>>>>>> No, it seems that YOU are not up to it, as you can't seem to 
>>>>>>>>>> understand the error that you are making.
>>>>>>>>>>
>>>>>>>>>> You keep on lying to yourself about what your requirements are.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I am not the one that keeps using the strawman deception to change
>>>>>>>>> the subject away from H(D,D) an abort decider for the above D.
>>>>>>>>
>>>>>>>> Neither am I.
>>>>>>>>
>>>>>>>> YOU agreed that the criteria for an abort decider is only 
>>>>>>>> CORRECT if a CORRECT simulation of the exact input given to 
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