Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: "Fred. Zwarts" Newsgroups: comp.theory Subject: Re: Turing Machine computable functions apply finite string transformations to inputs VERIFIED FACT Date: Tue, 29 Apr 2025 08:29:50 +0200 Organization: A noiseless patient Spider Lines: 84 Message-ID: References: <0a2eeee6cb4b6a737f6391c963386745a09c8a01@i2pn2.org> <4818688e0354f32267e3a5f3c60846ae7956bed2@i2pn2.org> <65dddfad4c862e6593392eaf27876759b1ed0e69@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Tue, 29 Apr 2025 08:29:51 +0200 (CEST) Injection-Info: dont-email.me; posting-host="096ac24e5d69209b585b797d85585ada"; logging-data="1250139"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18rdJ9kIgF9aEvhdu+ZSEyt" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:/FF5SbfnUpSQP2LWEQ1q7HPqUMw= In-Reply-To: Content-Language: nl, en-GB Bytes: 5379 Op 29.apr.2025 om 06:57 schreef olcott: > On 4/28/2025 10:00 PM, dbush wrote: >> On 4/28/2025 10:50 PM, olcott wrote: >>> On 4/28/2025 3:13 PM, Richard Heathfield wrote: >>>> On 28/04/2025 19:30, olcott wrote: >>>>> On 4/28/2025 11:38 AM, Richard Heathfield wrote: >>>>>> On 28/04/2025 16:01, olcott wrote: >>>>>>> On 4/28/2025 2:33 AM, Richard Heathfield wrote: >>>>>>>> On 28/04/2025 07:46, Fred. Zwarts wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> So we agree that no algorithm exists that can determine for all >>>>>>>>> possible inputs whether the input specifies a program that >>>>>>>>> (according to the semantics of the machine language) halts when >>>>>>>>> directly executed. >>>>>>>>> Correct? >>>>>>>> >>>>>>>> Correct. We can, however, construct such an algorithm just as >>>>>>>> long as we can ignore any input we don't like the look of. >>>>>>>> >>>>>>> >>>>>>> The behavior of the direct execution of DD cannot be derived >>>>>>> by applying the finite string transformation rules specified >>>>>>> by the x86 language to the input to HHH(DD). This proves that >>>>>>> this is the wrong behavior to measure. >>>>>>> >>>>>>> It is the behavior THAT IS derived by applying the finite >>>>>>> string transformation rules specified by the x86 language >>>>>>> to the input to HHH(DD) proves that THE EMULATED DD NEVER HALTS. >>>>>> >>>>>> The x86 language is neither here nor there. >>>>> >>>>> Computable functions are the formalized analogue >>>>> of the intuitive notion of algorithms, in the sense >>>>> that a function is computable if there exists an >>>>> algorithm that can do the job of the function, i.e. >>>>> *given an input of the function domain it* >>>>> *can return the corresponding output* >>>>> https://en.wikipedia.org/wiki/Computable_function >>>>> >>>>> *Outputs must correspond to inputs* >>>>> >>>>> *This stipulates how outputs must be derived* >>>>> Every Turing Machine computable function is >>>>> only allowed to derive outputs by applying >>>>> finite string transformation rules to its inputs. >>>> >>>> In your reply to my article, you forgot to address what I actually >>>> wrote. I'm not sure you understand what 'reply' means. >>>> >>>> Still, I'm prepared to give you another crack at it. Here's what I >>>> wrote before: >>>> >>>> What matters is whether a TM can be constructed that can accept an >>>> arbitrary TM tape P and an arbitrary input tape D and correctly >>>> calculate whether, given D as input, P would halt. Turing proved >>>> that such a TM cannot be constructed. >>>> >>>> This is what we call the Halting Problem. >>>> >>> >>> Yet it is H(P,D) and NOT P(D) that must be measured. >> >> Not if it's the behavior of P(D) we want to know about, which it is. >> > > Wanting the square root of a rotten egg would do as well. > When P defines a pathological relationship with H it > is stupidly incorrect to expect the behavior of P to remain the same. > The square root of a rotten egg does not exist. The behaviour of P(D) does exist. That you cannot even see such simple facts makes that you don't understand simple requirements. One thing was correct: Op 17.apr.2025 om 06:05 schreef olcott: >... > > Flibble and I did not solve the Halting Problem