Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: dbush Newsgroups: comp.theory Subject: Re: Every sufficiently competent C programmer knows --- Paraphrase of Sipser's agreement Date: Sun, 16 Mar 2025 11:32:23 -0400 Organization: A noiseless patient Spider Lines: 163 Message-ID: References: <1571d378add9779a0986b4df903964c7241f94a7@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 16 Mar 2025 16:32:23 +0100 (CET) Injection-Info: dont-email.me; posting-host="67c63d6f95dcce4899f1b1432e20e56d"; logging-data="2150429"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19y/y1C3GyTEVc+PNSL6V0a" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:p3MRGZXmbDm1+r2f3XJz68BrV9U= Content-Language: en-US In-Reply-To: On 3/16/2025 11:05 AM, olcott wrote: > On 3/16/2025 7:31 AM, joes wrote: >> Am Sat, 15 Mar 2025 16:27:00 -0500 schrieb olcott: >>> On 3/15/2025 5:12 AM, Mikko wrote: >>>> On 2025-03-14 14:39:30 +0000, olcott said: >>>>> On 3/14/2025 4:03 AM, Mikko wrote: >>>>>> On 2025-03-13 20:56:22 +0000, olcott said: >>>>>>> On 3/13/2025 4:22 AM, Mikko wrote: >>>>>>>> On 2025-03-13 00:36:04 +0000, olcott said: >>>>>>>> >>>>>>>> >>>>>>>>> void DDD() >>>>>>>>> { >>>>>>>>>     HHH(DDD); >>>>>>>>>     return; >>>>>>>>> } >>>>>>>>> int DD() >>>>>>>>> { >>>>>>>>>     int Halt_Status = HHH(DD); >>>>>>>>>     if (Halt_Status) >>>>>>>>>       HERE: goto HERE; >>>>>>>>>     return Halt_Status; >>>>>>>>> } >>>>>>>>> >>>>>>>>> When HHH correctly emulates N steps of the above functions none of >>>>>>>>> them can possibly reach their own "return" instruction and >>>>>>>>> terminate normally. >>>>>>>> >>>>>>>> Nevertheless, assuming HHH is a decider, Infinite_Loop and >>>>>>>> Infinite_Recursion specify a non-terminating behaviour, DDD >>>>>>>> specifies a terminating behaviour >>>>>>> >>>>>>> What is the sequence of machine language instructions of DDD >>>>>>> emulated by HHH such that DDD reaches its machine address 00002183? >>>>>> >>>>>> Irrelevant off-topic distraction. >>>>> >>>>> Proving that you don't have a clue that Rice's Theorem is anchored in >>>>> the behavior that its finite string input specifies. >>>> >>>> Another irrelevant off-topic distraction, this time involving a false >>>> claim. >>>> One can be a competent C programmer without knowing anyting about >>>> Rice's Theorem. >>> YES. >>> >>>> Rice's Theorem is about semantic properties in general, not just >>>> behaviours. >>>> The unsolvability of the halting problem is just a special case. >>>> >>> Does THE INPUT TO simulating termination analyzer HHH encode a C >>> function that reaches its "return" >>> instruction [WHEN SIMULATED BY HHH] (The definition of simulating >>> termination analyzer) ??? > >> That can't be right. Otherwise my simulator could just not simulate >> at all and say that no input halts. >> > > Originally a "decider" was any TM that always stops > running for any reason. > > In computability theory, a decider is a Turing > machine that halts for every input.[1] > https://en.wikipedia.org/wiki/Decider_(Turing_machine) > >>> >>> >> key word "correctly" >> > > *I anchored what correct emulation means now* > > > If emulating termination analyzer H emulates its input > finite string D of x86 machine language instructions > according to the semantics of the x86 programming language > until H correctly determines that this emulated D cannot > possibly reach its own "ret" instruction in any finite > number of correctly emulated steps then > > H can abort its emulation of input D and correctly report > that D specifies a non-halting sequence of configurations. > > > Nope: On Monday, March 6, 2023 at 2:41:27 PM UTC-5, Ben Bacarisse wrote: > Fritz Feldhase writes: > > > On Monday, March 6, 2023 at 3:56:52 AM UTC+1, olcott wrote: > >> On 3/5/2023 8:33 PM, Fritz Feldhase wrote: > >> > On Monday, March 6, 2023 at 3:30:38 AM UTC+1, olcott wrote: > >> > > > >> > > I needed Sipser for people [bla] > >> > > > >> > Does Sipser support your view/claim that you have refuted the halting theorem? > >> > > >> > Does he write/teach that the halting theorem is invalid? > >> > > >> > Tell us, oh genius! > >> > > >> Professor Sipser only agreed that [...] > > > > So the answer is no. Noted. > > > >> Because he has >250 students he did not have time to examine anything > >> else. [...] > > > > Oh, a CS professor does not have the time to check a refutation of the > > halting theorem. *lol* > I exchanged emails with him about this. He does not agree with anything > substantive that PO has written. I won't quote him, as I don't have > permission, but he was, let's say... forthright, in his reply to me. > On 8/23/2024 5:07 PM, Ben Bacarisse wrote: > joes writes: > >> Am Wed, 21 Aug 2024 20:55:52 -0500 schrieb olcott: > >>> Professor Sipser clearly agreed that an H that does a finite simulation >>> of D is to predict the behavior of an unlimited simulation of D. >> >> If the simulator *itself* would not abort. The H called by D is, >> by construction, the same and *does* abort. > > We don't really know what context Sipser was given. I got in touch at > the time so do I know he had enough context to know that PO's ideas were > "wacky" and that had agreed to what he considered a "minor remark". > > Since PO considers his words finely crafted and key to his so-called > work I think it's clear that Sipser did not take the "minor remark" he > agreed to to mean what PO takes it to mean! My own take if that he > (Sipser) read it as a general remark about how to determine some cases, > i.e. that D names an input that H can partially simulate to determine > it's halting or otherwise. We all know or could construct some such > cases. > > I suspect he was tricked because PO used H and D as the names without > making it clear that D was constructed from H in the usual way (Sipser > uses H and D in at least one of his proofs). Of course, he is clued in > enough know that, if D is indeed constructed from H like that, the > "minor remark" becomes true by being a hypothetical: if the moon is made > of cheese, the Martians can look forward to a fine fondue. But, > personally, I think the professor is more straight talking than that, > and he simply took as a method that can work for some inputs. That's > the only way is could be seen as a "minor remark" with being accused of > being disingenuous. On 8/23/2024 9:10 PM, Mike Terry wrote: > So that PO will have no cause to quote me as supporting his case: what > Sipser understood he was agreeing to was NOT what PO interprets it as > meaning. Sipser would not agree that the conclusion applies in PO's > HHH(DDD) scenario, where DDD halts.