Path: ...!feed.opticnetworks.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 H0 -- Ben agrees that Sipser approved criteria is met Date: Thu, 27 Jun 2024 10:36:00 +0300 Organization: - Lines: 149 Message-ID: References: <87jzidm83f.fsf@bsb.me.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Thu, 27 Jun 2024 09:36:00 +0200 (CEST) Injection-Info: dont-email.me; posting-host="d7b27c8cdba91f30a1cc0e0727f68863"; logging-data="2782019"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+hhZi/Ln1F6CiQq2+EDS8M" User-Agent: Unison/2.2 Cancel-Lock: sha1:0f12koNbFSf82X099GnsHO5nVBs= Bytes: 8564 On 2024-06-26 12:58:59 +0000, olcott said: > On 6/26/2024 3:41 AM, Mikko wrote: >> On 2024-06-26 02:29:59 +0000, olcott said: >> >>> On 6/25/2024 9:23 PM, Richard Damon wrote: >>>> On 6/25/24 10:05 PM, olcott wrote: >>>>> On 6/25/2024 8:47 PM, Richard Damon wrote: >>>>>> On 6/25/24 1:45 PM, olcott wrote: >>>>>>> On 6/25/2024 9:46 AM, Alan Mackenzie wrote: >>>>>>>> Hi, Ben. >>>>>>>> >>>>>>>> Ben Bacarisse wrote: >>>>>>>>> Alan Mackenzie writes: >>>>>>>> >>>>>>>>>> In comp.theory olcott wrote: >>>>>>>>>>> On 6/25/2024 4:22 AM, joes wrote: >>>>>>>>>>>> Am Sat, 22 Jun 2024 13:47:24 -0500 schrieb olcott: >>>>>>>>>>>>> On 6/22/2024 1:39 PM, Fred. Zwarts wrote: >>>>>>>>>>>>>> Op 21.jun.2024 om 15:21 schreef olcott: >>>>>>>> >>>>>>>>>>>>> When we stipulate that the only measure of a correct emulation is the >>>>>>>>>>>>> semantics of the x86 programming language then we see that when DDD is >>>>>>>>>>>>> correctly emulated by H0 that its call to H0(DDD) cannot possibly >>>>>>>>>>>>> return. >>>>>>>>>>>> Yes. Which is wrong, because H0 should terminate. >>>>>>>> >>>>>>>>>> [ .... ] >>>>>>>> >>>>>>>>>>> The call from DDD to H0(DDD) when DDD is correctly emulated >>>>>>>>>>> by H0 cannot possibly return. >>>>>>>> >>>>>>>>>>> Until you acknowledge this is true, this is the >>>>>>>>>>> only thing that I am willing to talk to you about. >>>>>>>> >>>>>>>>>> I think you are talking at cross purposes.  Joes's point is that H0 >>>>>>>>>> should terminate because it's a decider.  You're saying that when H0 is >>>>>>>>>> "correctly" emulating, it won't terminate.  I don't recall seeing anybody >>>>>>>>>> arguing against that. >>>>>>>> >>>>>>>>>> So you're saying, in effect, H0 is not a decider.  I don't think anybody >>>>>>>>>> else would argue against that, either. >>>>>>>> >>>>>>>>> He's been making exactly the same nonsense argument for years.  It >>>>>>>>> became crystal clear a little over three years ago when he made the >>>>>>>>> mistake of posting the pseudo-code for H -- a step by step simulator >>>>>>>>> that stopped simulating (famously on line 15) when some pattern was >>>>>>>>> detected.  He declared false (not halting) to be the correct result for >>>>>>>>> the halting computation H(H_Hat(), H_Hat()) because of what H(H_Hat(), >>>>>>>>> H_Hat()) would do "if line 15 were commented out"! >>>>>>>> >>>>>>>>> PO does occasionally make it clear what the shell game is. >>>>>>>> >>>>>>>> I think it's important for (relative) newcomers to the newsgroup to >>>>>>>> become aware of this.  Each one of them is trying to help PO improve his >>>>>>>> level of learning.  They will eventually give up, as you and I have >>>>>>>> done, recognising (as Mike Terry, in particular, has done) that >>>>>>>> enriching PO's intellect is a quite impossible task. >>>>>>>> >>>>>>>> What's the betting he'll respond to this post with his usual short >>>>>>>> sequence of x86 assembly code together with a demand to recognise >>>>>>>> something or other as non-terminating? >>>>>>>> >>>>>>>>> -- >>>>>>>>> Ben. >>>>>>>> >>>>>>> >>>>>>> >>>>>>>      If simulating halt decider H correctly simulates its input D >>>>>>>      until H correctly determines that its simulated D would never >>>>>>>      stop running unless aborted then >>>>>>> >>>>>>>      H can abort its simulation of D and correctly report that D >>>>>>>      specifies a non-halting sequence of configurations. >>>>>>> >>>>>>> >>>>>>> On 10/14/2022 7:44 PM, Ben Bacarisse wrote: >>>>>>>  > I don't think that is the shell game. PO really /has/ an H >>>>>>>  > (it's trivial to do for this one case) that correctly determines >>>>>>>  > that P(P) *would* never stop running *unless* aborted. >>>>>>>  > >>>>>>>  > He knows and accepts that P(P) actually does stop. The >>>>>>>  > wrong answer is justified by what would happen if H >>>>>>>  > (and hence a different P) where not what they actually are. >>>>>>>  > >>>>>>> >>>>>>> Ben thinks that I tricked professor Sipser into agreeing >>>>>>> with something that he did not fully understand. >>>>>>> >>>>>>> *The real issue is that no one here sufficiently understands* >>>>>>> *the highlighted portion of the following definition* >>>>>>> >>>>>>> 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 >>>>>>> >>>>>>> >>>>>> >>>>>> But only if the function is, in fact, computable. >>>>>> >>>>>> Since Halting isn't, you can't use that fact. >>>>> >>>>> If I ask you: What time is it? >>>>> and you do not tell me the answer to the question hidden >>>>> in my mind "What did you have for dinner?" We cannot say >>>>> that you provided the wrong answer when you tell me what >>>>> time it is. >>>> >>>> Because I answered the actual question. >>>> >>>> Just like the "Halt Decider" needs to answer the "Halt Decider >>>> Question" and not answer about POOP. >>>> >>>>> >>>>> When we ask H to tell us whether its actual input halts >>>>> H can only answer that P correctly simulated by H will not halt. >>>>> H cannot answer the question hidden in your mind. >>>>> >>>> >>>> Then you are just admitting that it can't be a Halt Decider. >>>> >>>> If it isn't what the definition requires, it just isn't one. >>> >>> Yes and everyone knows that computer scientists are much >>> more infallible than God thus cannot possibly ever make >>> a definition that is incoherent in ways that these 100% >>> infallible computer scientists never noticed. >> >> Actually, it is the opposite. Everybody, or at least all computer >> scientists and engineers, know that they, and all peaple, are fallible, >> at least when making programs and when inferring about programs. Therefore >> computer engineers demand that every program must be tested, and computer >> scinetists demand that every claim is proven. > > If this was true then everyone here would already know > that H(P,P) is not even being asked about the behavior > of the directly executed P(P). Everyone knwos that H(P,P) is not asked anything. -- Mikko