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On 5/11/2025 7:38 PM, Mike Terry wrote:No it doesn't.On 11/05/2025 18:11, Richard Heathfield wrote:DDD emulated by HHH according to the rules ofOn 11/05/2025 17:44, olcott wrote:>Any yes/no question where both yes and no are the>
wrong answer is an incorrect polar question.
Either DD stops or it doesn't (once it's been hacked around to get it to compile and after we've leeched out all the dodgy programming).
Done that. It still stops.
>>>
If the computer cannot correctly decide whether or not DD halts,
The decider says it doesn't stop..
>we have an undecidable computation,>
No no, that doesn't make sense. DD stops, and there are lots of partial halt deciders that will decide that particular input correctly. PO's DD isn't "undecidable".
>
No single computation can be undecidable, considered on its own! There are only two possibilities: it halts or it doesn't. In either case there is a decider which decides that /one specific input/ correctly. By extension, any finite number of computations is decidable - we just have a giant switch statement followed by returning halts/neverhalts as appropriate. If the input domain has just n inputs, there are 2^n trivial deciders that together cater for every combination of each input halting or never halting. One of those deciders is a correct decider for that (finite domain) problem.
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The HP is asking for a TM (or equiv.) that correctly decides EVERY (P,I) in its one finite algorithm. That is what is proven impossible. The trick of having a big switch statement no longer works because there are infinitely many possible inputs.
>
Decidability for just one single input is trivial and not intersting.
>and therefore some computations are undecidable, so Turing's conclusion was right. Who knew? (Apart from practically everybody else, I mean.)>
>
Mike.
the computational language that DD is encoded
within already proves that the HP "impossible"
input specifies a non-halting sequence of
configurations.
The same goes for the Linz proof.Right, H <H^> <H^> is wrong to say non-halting as H^ <H^> will use its copy of H applied to <H^> <H^> see that it went to qn and then it will halt.
The mistake is continuing to assume that aBut the behavor of its input *IS* the behavior of running the program the input specifies, which is exactly what you are trying to deny.
termination analyzer must report on behavior
other than the behavior that its input specifies.
When an input is simulated according toRight, and that is NOT the results of the partial simulation done by HHH, but the actual correct simulation done by giving that exact input (which still calls the HHH that does the aborting that the HHH you claim is correct does) and thus we see DDD calll HHH(DDD) which will emulate DDD for some number of steps, then abort its emulation because it (erroneously) thinks that the input represent a non-halting program due to a incorrect pattern programmed into it, and it then returns to DDD which then halts.
the behavior specified by the computation
language that it is encoded within
THEN THIS SIMULATION IS CORRECT.
It seems nuts (or dishonest) to claim otherwise.
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