Path: ...!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Mikko Newsgroups: comp.theory Subject: Re: DDD correctly emulated by HHH is Correctly rejected as non-halting V2 Date: Tue, 23 Jul 2024 09:32:57 +0300 Organization: - Lines: 67 Message-ID: References: <3fc6548531f91ed14a27420caf9679a634573ed0@i2pn2.org> <8a6e6d9ff49aabe2525ce5729a439c807de4768a@i2pn2.org> <34Ocnd4voeWlDAn7nZ2dnZfqnPudnZ2d@brightview.co.uk> <056325e336f81a50f4fb9e60f90934eaac823d22@i2pn2.org> <210383b2ee318f68a96d94aec314ee8b93f79b7f@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 23 Jul 2024 08:32:58 +0200 (CEST) Injection-Info: dont-email.me; posting-host="b538c18a808e7b1dbb2e6c99920961e5"; logging-data="1163821"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19cAnWSg9qinNLVzHcuVWp1" User-Agent: Unison/2.2 Cancel-Lock: sha1:8Lu+ua3sJjchcD96STlEPZ0gsTM= Bytes: 4292 On 2024-07-22 13:46:21 +0000, olcott said: > On 7/22/2024 2:57 AM, Mikko wrote: >> On 2024-07-21 13:34:40 +0000, olcott said: >> >>> On 7/21/2024 4:34 AM, Mikko wrote: >>>> On 2024-07-20 13:11:03 +0000, olcott said: >>>> >>>>> On 7/20/2024 3:21 AM, Mikko wrote: >>>>>> On 2024-07-19 14:08:24 +0000, olcott said: >>>>>> >>>>>>> When we use your incorrect reasoning we would conclude >>>>>>> that Infinite_Loop() is not an infinite loop because it >>>>>>> only repeats until aborted and is aborted. >>>>>> >>>>>> You and your HHH can reason or at least conclude correctly about >>>>>> Infinite_Loop but not about DDD. Possibly because it prefers to >>>>>> say "no", which is correct about Infinte_loop but not about DDD. >>>>>> >>>>> >>>>> *Because this is true I don't understand how you are not simply lying* >>>>> int main >>>>> { >>>>>    DDD(); >>>>> } >>>>> >>>>> Calls HHH(DDD) that must abort the emulation of its input >>>>> or {HHH, emulated DDD and executed DDD} never stop running. >>>> >>>> You are the lying one. >>>> >>>> If HHH(DDD) abrots its simulation and returns true it is correct as a >>>> halt decider for DDD really halts. >>>> >>> >>> (b) We know that a decider is not allowed to report on the behavior >>> computation that itself is contained within. >> >> No, we don't. There is no such prohibition. >> > > Turing machines never take actual Turing machines as inputs. > They only take finite strings as inputs and an actual executing > Turing machine is not itself a finite string. The definition of a Turing machine does not say that a Turing machine is not a finite string. It is an abstract mathematical object without a specification of its exact nature. It could be a set or a finite string. Its exact nature is not relevant to the theory of computation, which only cares about certain properties of Turing machines. > Therefore It is not allowed to report on its own behavior. Anyway, that does not follow. The theory of Turing machines does not prohibit anything. > Another different TM can take the TM description of this > machine and thus accurately report on its actual behavior. If a Turing machine can take a description of a TM as its input or as a part of its input it can also take its own description. Every Turing machine can be given its own description as input but a Turing machine may interprete it as something else. -- Mikko