Path: ...!eternal-september.org!feeder3.eternal-september.org!news.quux.org!news.nk.ca!rocksolid2!i2pn2.org!.POSTED!not-for-mail From: Richard Damon Newsgroups: comp.theory Subject: Re: DD specifies non-terminating behavior to HHH --- ONE POINT AT A TIME !!! Date: Wed, 19 Feb 2025 21:14:08 -0500 Organization: i2pn2 (i2pn.org) Message-ID: References: <3b8a5f4be53047b2a6c03f9678d0253e137d3c40@i2pn2.org> <5cd9bc55c484f10efd7818ecadf169a11fcc58e1@i2pn2.org> <442891e4193f52206ec1b8481f5c2688de58b305@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Thu, 20 Feb 2025 02:14:09 -0000 (UTC) Injection-Info: i2pn2.org; logging-data="869904"; mail-complaints-to="usenet@i2pn2.org"; posting-account="diqKR1lalukngNWEqoq9/uFtbkm5U+w3w6FQ0yesrXg"; User-Agent: Mozilla Thunderbird X-Spam-Checker-Version: SpamAssassin 4.0.0 In-Reply-To: Content-Language: en-US Bytes: 9250 Lines: 177 On 2/19/25 7:34 PM, olcott wrote: > On 2/19/2025 4:55 AM, Fred. Zwarts wrote: >> Op 18.feb.2025 om 17:48 schreef olcott: >>> On 2/18/2025 8:11 AM, Fred. Zwarts wrote: >>>> Op 18.feb.2025 om 14:37 schreef olcott: >>>>> On 2/18/2025 6:25 AM, Richard Damon wrote: >>>>>> On 2/18/25 6:26 AM, olcott wrote: >>>>>>> On 2/18/2025 3:24 AM, Mikko wrote: >>>>>>>> On 2025-02-17 09:05:42 +0000, Fred. Zwarts said: >>>>>>>> >>>>>>>>> Op 16.feb.2025 om 23:51 schreef olcott: >>>>>>>>>> On 2/16/2025 4:30 PM, joes wrote: >>>>>>>>>>> Am Sun, 16 Feb 2025 15:58:14 -0600 schrieb olcott: >>>>>>>>>>>> On 2/16/2025 2:02 PM, joes wrote: >>>>>>>>>>>>> Am Sun, 16 Feb 2025 13:24:14 -0600 schrieb olcott: >>>>>>>>>>>>>> On 2/16/2025 10:35 AM, joes wrote: >>>>>>>>>>>>>>> Am Sun, 16 Feb 2025 06:51:12 -0600 schrieb olcott: >>>>>>>>>>>>>>>> On 2/15/2025 2:49 AM, Mikko wrote: >>>>>>>>>>>>>>>>> On 2025-02-14 12:40:04 +0000, olcott said: >>>>>>>>>>>>>>>>>> On 2/14/2025 2:58 AM, Mikko wrote: >>>>>>>>>>>>>>>>>>> On 2025-02-14 00:07:23 +0000, olcott said: >>>>>>>>>>>>>>>>>>>> On 2/13/2025 3:20 AM, Mikko wrote: >>>>>>>>>>>>>>>>>>>>> On 2025-02-13 04:21:34 +0000, olcott said: >>>>>>>>>>>>>>>>>>>>>> On 2/12/2025 4:04 AM, Mikko wrote: >>>>>>>>>>>>>>>>>>>>>>> On 2025-02-11 14:41:38 +0000, olcott said: >>>>>>>>>>> >>>>>>>>>>>>>>>>>> DD  correctly simulated by HHH cannot possibly >>>>>>>>>>>>>>>>>> terminate normally. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> That claim has already shown to be false. Nothing above >>>>>>>>>>>>>>>>> shows that >>>>>>>>>>>>>>>>> HHH does not return 0. If it does DD also returns 0. >>>>>>>>>>>>>>>> When we are referring to the above DD simulated by HHH >>>>>>>>>>>>>>>> and not >>>>>>>>>>>>>>>> trying to get away with changing the subject to some >>>>>>>>>>>>>>>> other DD >>>>>>>>>>>>>>>> somewhere else >>>>>>>>>>>>>>> such as one that calls a non-aborting version of HHH >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> then anyone with sufficient knowledge of C programming >>>>>>>>>>>>>>>> knows that no >>>>>>>>>>>>>>>> instance of DD shown above simulated by any >>>>>>>>>>>>>>>> corresponding instance >>>>>>>>>>>>>>>> of HHH can possibly terminate normally. >>>>>>>>>>>>>>> Well, then that corresponding (by what?) HHH isn’t a >>>>>>>>>>>>>>> decider. >>>>>>>>>>>>>> I am focusing on the isomorphic notion of a termination >>>>>>>>>>>>>> analyzer. >>>>>>>>>>>>> (There are other deciders that are not termination analysers.) >>>>>>>>>>>>> >>>>>>>>>>>>>> A simulating termination analyzer correctly rejects any >>>>>>>>>>>>>> input that >>>>>>>>>>>>>> must be aborted to prevent its own non-termination. >>>>>>>>>>>>> Yes, in particular itself is not such an input, because we >>>>>>>>>>>>> *know* that >>>>>>>>>>>>> it halts, because it is a decider. You can’t have your cake >>>>>>>>>>>>> and eat it >>>>>>>>>>>>> too. >>>>>>>>>>>> I am not even using the confusing term "halts". >>>>>>>>>>>> Instead I am using in its place "terminates normally". >>>>>>>>>>>> DD correctly simulated by HHH cannot possibly terminate >>>>>>>>>>>> normally. >>>>>>>>>>> What’s confusing about „halts”? I find it clearer as it does >>>>>>>>>>> not imply >>>>>>>>>>> an ambiguous „abnormal termination”. How does HHH simulate DD >>>>>>>>>>> terminating abnormally, then? Why doesn’t it terminate >>>>>>>>>>> abnormally >>>>>>>>>>> itself? >>>>>>>>>>> You can substitute the term: the input DD to HHH does not >>>>>>>>>>> need to be >>>>>>>>>>> aborted, because the simulated decider terminates. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> 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() >>>>>>>>>> { >>>>>>>>>>   HHH(DD); >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> Every simulated input that must be aborted to >>>>>>>>>> prevent the non-termination of HHH is stipulated >>>>>>>>>> to be correctly rejected by HHH as non-terminating. >>>>>>>>>> >>>>>>>>> A very strange and invalid stipulation. >>>>>>>> >>>>>>>> It merely means that the words do not have their ordinary meaning. >>>>>>>> >>>>>>> >>>>>>> Unless HHH(DD) aborts its simulation of DD itself cannot possibly >>>>>>> terminate normally. Every expert in the C programming language >>>>>>> can see this. People that are not experts get confused by the loop >>>>>>> after the "if" statement. >>>>>>> >>>>>> >>>>>> So? Since it does that, it needs to presume that the copy of >>>>>> itself it sees called does that. >>>>>> >>>>> >>>>> Not at all. Perhaps your technical skill is much more woefully >>>>> deficient than I ever imagined. >>>>> >>>>> Here is the point that you just missed Unless the first HHH >>>>> that sees the non-terminating pattern aborts its simulation >>>>> none of them do because they all have the exact same code. >>>>> >>>>> >>>> >>>> The point Olcott misses is that if the non-terminating HHH is >>>> changed to abort the simulation, the program is changed. He does not >>>> understand that a modification of a program makes a change. Such a >>>> change modifies the behaviour of the program. The non-termination >>>> behaviour has disappeared with this change and only remains in his >>>> dreams. After this change, the simulation would terminate normally >>>> and HHH should no longer abort. But it does, because the code that >>>> detects the 'special condition' has a bug, which makes that it does >>>> not see that the program has been changed into a halting program. >>> >>> >>> When I focus on one single-point: >>> I get two years of dodging and this point is never addressed. >>> >>> [DD simulated by HHH cannot possibly terminate normally] >>> >>> void DDD() >>> { >>>    HHH(DDD); >>>    return; >>> } >>> >>> int main() >>> { >>>    HHH(Infinite_Recursion); >>>    HHH(DDD); >>> } >>> >> It is not true that this point has never been addressed. Olcott >> ignores it when it is addressed. >> >> What is the point? Even if HHH fails to simulate the halting program >> DD up to the end because it is logically impossible for it to complete >> the simulation, it still fails. > > It fails In the same way that every CAD system > will never correctly represent a geometric circle that has > four equal length sides in the same two dimensional plane. > But no one asks for that, because it is meaningless. Asking if a program will halt is not meaningless. ========== REMAINDER OF ARTICLE TRUNCATED ==========