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Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: olcott <polcott333@gmail.com> Newsgroups: comp.theory Subject: Re: DDD correctly emulated by HHH is correctly rejected as non-halting. --- You are not paying attention Date: Fri, 19 Jul 2024 08:48:49 -0500 Organization: A noiseless patient Spider Lines: 109 Message-ID: <v7dqs3$30pvh$1@dont-email.me> References: <v6m7si$1uq86$2@dont-email.me> <v6mhc7$20hbo$2@dont-email.me> <v6mito$bbr$1@news.muc.de> <v6mjlg$20sio$2@dont-email.me> <v6mlfj$bbr$2@news.muc.de> <v6mlk6$21d9q$1@dont-email.me> <v6nu2n$2bepp$1@dont-email.me> <v6op7v$2fuva$5@dont-email.me> <v6qoms$2ukg7$1@dont-email.me> <v6rat7$30qtt$8@dont-email.me> <v6repr$32501$2@dont-email.me> <v6tbpe$3gg4d$1@dont-email.me> <v6traj$3imib$7@dont-email.me> <v703f7$2ooi$2@dont-email.me> <v70of6$61d8$8@dont-email.me> <v72kp6$k3b1$1@dont-email.me> <v738db$mjis$14@dont-email.me> <v756r9$15qot$1@dont-email.me> <v7614g$19j7l$11@dont-email.me> <v77qm6$1ntfr$1@dont-email.me> <v78g43$1rc43$5@dont-email.me> <v7ahpv$2arco$1@dont-email.me> <v7b5pl$2e2aq$3@dont-email.me> <v7d4mr$2svvi$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Fri, 19 Jul 2024 15:48:52 +0200 (CEST) Injection-Info: dont-email.me; posting-host="806954090dbe9e2c0be16c7a3e599476"; logging-data="3172337"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18zZXtsRPCC9YL6S6TAg1CN" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:rciXwFszMK8fEhxfNNxwKQjxmt8= Content-Language: en-US In-Reply-To: <v7d4mr$2svvi$1@dont-email.me> Bytes: 5700 On 7/19/2024 2:30 AM, Mikko wrote: > On 2024-07-18 13:36:53 +0000, olcott said: > >> On 7/18/2024 2:55 AM, Mikko wrote: >>> On 2024-07-17 13:14:43 +0000, olcott said: >>> >>>> On 7/17/2024 2:08 AM, Mikko wrote: >>>>> On 2024-07-16 14:46:40 +0000, olcott said: >>>>> >>>>>> On 7/16/2024 2:18 AM, Mikko wrote: >>>>>>> On 2024-07-15 13:32:27 +0000, olcott said: >>>>>>> >>>>>>>> On 7/15/2024 2:57 AM, Mikko wrote: >>>>>>>>> On 2024-07-14 14:48:05 +0000, olcott said: >>>>>>>>> >>>>>>>>>> On 7/14/2024 3:49 AM, Mikko wrote: >>>>>>>>>>> On 2024-07-13 12:18:27 +0000, olcott said: >>>>>>>>>> >>>>>>>>>> When the source of your disagreement is your own ignorance >>>>>>>>>> then your disagreement has no actual basis. >>>>>>>>>> >>>>>>>>>> *You can comprehend this is a truism or fail to* >>>>>>>>>> *comprehend it disagreement is necessarily incorrect* >>>>>>>>>> Any input that must be aborted to prevent the non >>>>>>>>>> termination of HHH necessarily specifies non-halting >>>>>>>>>> behavior or it would never need to be aborted. >>>>>>>>>> >>>>>>>>>> Disagreeing with the above is analogous to disagreeing >>>>>>>>>> with arithmetic. >>>>>>>>> >>>>>>>>> A lame analogy. A better one is: 2 + 3 = 5 is a proven theorem >>>>>>>>> just >>>>>>>>> like the uncomputability of halting is. >>>>>>>> >>>>>>>> The uncomputability of halting is only proven when the problem >>>>>>>> is framed this way: HHH is required to report on the behavior >>>>>>>> of an input that was defined to do exactly the opposite of >>>>>>>> whatever DDD reports. >>>>>>> >>>>>>> No, it is proven about the halting problem as that problem is. >>>>>> >>>>>> Which is simply a logical impossibility >>>>> >>>>> Yes, a halting decider is a logical impossibility, as can be and has >>>>> been proven. >>>> >>>> If it is a logical impossibility then it places no >>>> actual limit on computation otherwise we would have >>>> "the CAD problem" of the logical impossibility of making >>>> a CAD system that correctly draws a square circle. >>> >>> A logical impossibility does place a limit on computation. >>> Otherwise it would be possible to build a CAD system that >>> can correctly draw a square circle. >> >> Of the set of possible things TM's can do them all. > > Depends on the meanings of "possible" and "thing". Of things other than > computation no TM can do any. A Turing machine can determine whether > a sentence of Presburger arithmetic is provable but no Turing machine > can determine whether a sentence of Peano arithmetic is provable. > Some undecidable expressions are only undecidable because they are self contradictory. In other words they are undecidable because there is something wrong with them. The Liar Paradox: "This sentence is not true" (is neither true nor false) and the HP proof are that way, yet, only when we expect a decider to return the halt status of an input that does that opposite of whatever value the decider returns. typedef void (*ptr)(); int HHH(ptr P); int DD() { int Halt_Status = HHH(DD); if (Halt_Status) HERE: goto HERE; return Halt_Status; } int main() { DD(); } *When we understand that* (a) The halt decider is not allowed to report on the computation that it is contained within. Then the behavior of the directly executed DD() is moot. (b) The self-contradictory part of the input is unreachable from the emulated DD then a simulating partial halt decider does correctly compute the mapping from the input finite string to the non-halting behavior of this finite string. int main { DD(); } calls HHH(DD) that must abort the emulation of its input or HHH, emulated DD and executed DD never stop running. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer