Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Mikko Newsgroups: comp.theory Subject: Re: How do computations actually work? Date: Wed, 28 May 2025 10:38:54 +0300 Organization: - Lines: 141 Message-ID: <1016eie$352vc$1@dont-email.me> References: <100l1ov$2ul3j$1@dont-email.me> <100l3jh$2v0e9$1@dont-email.me> <100l5c8$2ul3j$2@dont-email.me> <100l75g$2vpq3$1@dont-email.me> <100l887$2ul3i$2@dont-email.me> <100l9gh$30aak$1@dont-email.me> <100lc4o$30pgm$1@dont-email.me> <100ld1u$312c9$1@dont-email.me> <100lg4g$31jt3$1@dont-email.me> <100lkdv$32ib3$1@dont-email.me> <100lmif$32v06$1@dont-email.me> <100lmp3$32ven$1@dont-email.me> <100m319$38k55$2@dont-email.me> <87jz69xlpx.fsf@nosuchdomain.example.com> <100mder$39slu$2@dont-email.me> <100oipb$3oge1$1@dont-email.me> <100onkd$3t5cb$1@dont-email.me> <100p6vj$3vlgq$1@dont-email.me> <100q6b1$5buc$2@dont-email.me> <100rtvq$ji9l$1@dont-email.me> <100sod2$p071$6@dont-email.me> <100umo8$1a058$1@dont-email.me> <100vaoj$1d5lg$9@dont-email.me> <10119a9$1tver$1@dont-email.me> <10122jj$22da5$7@dont-email.me> <10123fp$22udp$2@dont-email.me> <10124o8$22da5$17@dont-email.me> <1013t99$2hhmd$1@dont-email.me> <1014mf3$2lsi8$9@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 28 May 2025 09:38:54 +0200 (CEST) Injection-Info: dont-email.me; posting-host="4d65ac626a85e0b2f5d51ba1a2ed3e15"; logging-data="3312620"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19CHGlm8BNFD0np8GVzuadc" User-Agent: Unison/2.2 Cancel-Lock: sha1:9dJHniJkY5RpvBlLkfxqSEBQYBg= On 2025-05-27 15:41:23 +0000, olcott said: > On 5/27/2025 3:31 AM, Mikko wrote: >> On 2025-05-26 16:26:47 +0000, olcott said: >> >>> On 5/26/2025 11:05 AM, Fred. Zwarts wrote: >>>> Op 26.mei.2025 om 17:50 schreef olcott: >>>>> On 5/26/2025 3:38 AM, Mikko wrote: >>>>>> On 2025-05-25 14:50:58 +0000, olcott said: >>>>>> >>>>>>> On 5/25/2025 4:09 AM, Mikko wrote: >>>>>>>> On 2025-05-24 15:25:21 +0000, olcott said: >>>>>>>> >>>>>>>>> On 5/24/2025 2:54 AM, Mikko wrote: >>>>>>>>>> On 2025-05-23 16:04:49 +0000, olcott said: >>>>>>>>>> >>>>>>>>>>> On 5/23/2025 2:09 AM, Mikko wrote: >>>>>>>>>>>> On 2025-05-23 02:47:40 +0000, olcott said: >>>>>>>>>>>> >>>>>>>>>>>>> On 5/22/2025 8:24 PM, Mike Terry wrote: >>>>>>>>>>>>>> On 22/05/2025 06:41, Richard Heathfield wrote: >>>>>>>>>>>>>>> On 22/05/2025 06:23, Keith Thompson wrote: >>>>>>>>>>>>>>>> Richard Heathfield writes: >>>>>>>>>>>>>>>>> On 22/05/2025 00:14, olcott wrote: >>>>>>>>>>>>>>>>>> On 5/21/2025 6:11 PM, Richard Heathfield wrote: >>>>>>>>>>>>>>>> [...] >>>>>>>>>>>>>>>>>>> Turing proved that what you're asking is impossible. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> That is not what he proved. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Then you'll be able to write a universal termination analyser that can >>>>>>>>>>>>>>>>> correctly report for any program and any input whether it halts. Good >>>>>>>>>>>>>>>>> luck with that. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Not necessarily. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Of course not. But I'm just reflecting. He seemed to think that my >>>>>>>>>>>>>>> inability to write the kind of program Turing envisaged (an inability >>>>>>>>>>>>>>> that I readily concede) is evidence for his argument. Well, what's >>>>>>>>>>>>>>> sauce for the goose is sauce for the gander. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Even if olcott had refuted the proofs of the >>>>>>>>>>>>>>>> insolvability of the Halting Problem -- or even if he had proved >>>>>>>>>>>>>>>> that a universal halt decider is possible >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> And we both know what we both think of that idea. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> -- that doesn't imply >>>>>>>>>>>>>>>> that he or anyone else would be able to write one. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Indeed. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> I've never been entirely clear on what olcott is claiming. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Nor I. Mike Terry seems to have a pretty good handle on it, but no >>>>>>>>>>>>>>> matter how clearly he explains it to me my eyes glaze over and I start >>>>>>>>>>>>>>> to snore. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Hey, it's the way I tell 'em! >>>>>>>>>>>>>> >>>>>>>>>>>>>> Here's what the tabloids might have said about it, if it had made the >>>>>>>>>>>>>> front pages when the story broke: >>>>>>>>>>>>>> >>>>>>>>>>>>>>   COMPUTER BOFFIN IS TURING IN HIS GRAVE! >>>>>>>>>>>>>> >>>>>>>>>>>>>>   An Internet crank claims to have refuted Linz HP proof by creating a >>>>>>>>>>>>>>   Halt Decider that CORRECTLY decides its own "impossible input"! >>>>>>>>>>>>>>   The computing world is underwhelmed. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Better?  (Appologies for the headline, it's the best I could come up with.) >>>>>>>>>>>>>> >>>>>>>>>>>>>> Mike. >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> There is a key detail about ALL of these proofs >>>>>>>>>>>>> that no one has paid attention to for 90 years. >>>>>>>>>>>>> >>>>>>>>>>>>> It is impossible to define *AN INPUT* to HHH that >>>>>>>>>>>>> does the opposite of whatever value that HHH returns. >>>>>>>>>>>> >>>>>>>>>>>> That is a key detail about HHH. Your HHH is not a part of those proofs. >>>>>>>>>>> >>>>>>>>>>> All of the proofs work this same way. >>>>>>>>>> >>>>>>>>>> No, they don't. Some proofs derive the same conclusion with an essentially >>>>>>>>>> different approach. >>>>>>>>>> >>>>>>>>>> However, in spite of the differences, they do share a common fieature: >>>>>>>>>> your HHH is not a part of any of the proofs. >>>>>>>>> >>>>>>>>> All of the conventional proofs of the HP assume that >>>>>>>>> there is an *input D* that can actually do the opposite >>>>>>>>> of whatever value that HHH returns. >>>>>>>> >>>>>>>> Depends on what you mean by "conventional". If you merely mean proofs >>>>>>>> that apply ordinary logic then there are proofs with a different >>>>>>>> strategy. If you mean only proofs that use the same strategy that >>>>>>>> Turing used then you are closer to the truth. But there is no assumption >>>>>>>> about the exstence of such D. Its existence is proven. >>>>>>> >>>>>>> In seems that way until you pay much closer attention. >>>>>> >>>>>> No, it seems that way when you pay enough attention. >>>>>> >>>>>>> int main() >>>>>>> { >>>>>>>    DDD(); // The HHH that DDD calls cannot report on the >>>>>>> }        // behavior of its caller because it cannot see >>>>>>>           // is caller. >>>>>> >>>>>> If HHH is correctly constructed it does see DDD and everything DDD >>>>>> calls. Nothing else is relevant. >>>>>> >>>>> >>>>> Try to show how HHH can see anything about its own caller >>>>> when HHH is not even allowed to look at its caller. >>>>> >>>> >>>> It is irrelevant whether DDD is the caller of HHH or not. >>>> int main() >>>>  { >>>>     HHH(DDD); >>>>     return; >>>>  } >>>> >>>> Now HHH is not called from HHH, but has the same input and it should >>>> see that DDD includes the Halt7.c code, which aborts, so it should see: >>>> a halting program. >>> >>> In other words you fail to understand that >>> halting requires reaching a final halt state. >> >> It is a sin to present false claims about tother peoples understanding. > > You have acted like you don't know this. You always act like a liar. Not like a good liar but like a stupid liar. -- Mikko