Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.lang.c,comp.lang.c++ Subject: Re: D correctly simulated by H remains stuck in recursive simulation [good attempt] Date: Wed, 22 May 2024 16:26:08 -0500 Organization: A noiseless patient Spider Lines: 119 Message-ID: References: <87v837kinv.fsf@nosuchdomain.example.com> <5328d908ef5ddab316b1335538ea4b1c0892133b.camel@gmail.com> <04d9f4aa4d07f50724dc709c1dc9d79bcb5c6a55.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 22 May 2024 23:26:09 +0200 (CEST) Injection-Info: dont-email.me; posting-host="9557ecc38a2c6e613b1947df9dd7fc56"; logging-data="1442492"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/GC4i7jk8gAzya0msFBs/5" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:piTOt8ksauDT9eAqcxxTD2I14UI= Content-Language: en-US In-Reply-To: <04d9f4aa4d07f50724dc709c1dc9d79bcb5c6a55.camel@gmail.com> Bytes: 6600 On 5/22/2024 3:59 PM, wij wrote: > On Wed, 2024-05-22 at 15:04 -0500, olcott wrote: >> On 5/22/2024 11:11 AM, wij wrote: >>> On Wed, 2024-05-22 at 10:44 -0500, olcott wrote: >>>> On 5/22/2024 3:54 AM, David Brown wrote: >>>>> On 21/05/2024 23:56, olcott wrote: >>>>>> On 5/21/2024 4:34 PM, bart wrote: >>>>>>> On 21/05/2024 19:48, olcott wrote: >>>>>>>> On 5/21/2024 1:39 PM, Bonita Montero wrote: >>>>>>> >>>>>>>>> You're neither asking about a C- or C++ problem. >>>>>>>>> So use a proper newsgroup. >>>>>>>>> >>>>>>>> >>>>>>>> There is no other group that knows enough about the semantics of the >>>>>>>> C programming language and there is no other group still alive that >>>>>>>> knows enough about the semantics of programming languages. >>>>>>> >>>>>>> Then FFS take it to Reddit, where there are a myriad thriving forums, >>>>>>> rather than a dying usenet group populated by a few aging regulars. >>>>>>> >>>>>>> >>>>>> >>>>>> I have taken it to many different forums. >>>>>> This is one of two forums where someone actually answered the question. >>>>>> Two years ago someone answered the assembly language version of the >>>>>> question. I think the Reddit banned me for even asking the question. >>>>>> >>>>> >>>>> The /only/ reason you are not banned here is because unmoderated Usenet >>>>> groups cannot ban people. >>>>> >>>>> You post obsessively in many places, and face nothing but rejection, >>>>> ridicule, and banning.  Has it ever occurred to you to look for the >>>>> common factor here?  It is /you/, and the posts you make.  If you truly >>>>> want to make progress on your bizarre ideas, you are going to have to >>>>> re-think your strategy - it is entirely obvious to everyone that you >>>>> will not get the answers you are asking for here or anywhere else with >>>>> your current posting style. >>>>> >>>>> >>>> >>>> *On the other hand people could simply answer my question* >>>> *I only repeat it until it is answered* >>>> >>>> For every H/D pair matching the following template where >>>> H is a pure function: >>>> >>>> Does any D correctly simulated by H reach its own line 06 and >>>> halt or does the fact that D remains stuck in recursive simulation >>>> prevent that? >>>> >>>> typedef int (*ptr)();  // ptr is pointer to int function in C >>>> 00       int H(ptr p, ptr i); >>>> 01       int D(ptr p) >>>> 02       { >>>> 03         int Halt_Status = H(p, p); >>>> 04         if (Halt_Status) >>>> 05           HERE: goto HERE; >>>> 06         return Halt_Status; >>>> 07       } >>>> 08 >>>> 09       int main() >>>> 10       { >>>> 11         H(D,D); >>>> 12         return 0; >>>> 13       } >>>> >>>> It is trivial to see that for every H/D pair of the infinite >>>> set of H/D pairs that match the above template that >>>> >>>> D correctly simulated by H cannot possibly reach its own final >>>> state at line 06 and halt because D correctly simulated by >>>> H remains stuck in recursive simulation. >>>> >>>> This provides the basis for simulating termination analyzer H to >>>> correctly determine that the halting problem's counter-example >>>> input D cannot possibly halt. >>>> >>> >>> If H is truly a simulator, its function is expected to be equivalent to: >>> >>> int H(ptr x, ptr y) { >>>   x(y); >>>   return __WHATEVER; >>> } >>> >>> The H(D,D) can never halt. >>> >>> >> >> Finally someone took 30 seconds to answer, thanks! >> *The actual question was slightly different in a very crucial way* >> >> It is trivial to see that for every H/D pair of the infinite >> set of H/D pairs that match the above template that >> >> D correctly simulated by H cannot possibly reach its own final >> state at line 06 and halt because D correctly simulated by >> H remains stuck in recursive simulation. > > Correct. H will be stuck in the recursive simulations. > >> *In other words even when H(D,D) terminates normally D* >> *correctly simulated by H cannot possibly terminate normally* > > Correct. Because D is programmed to behave the opposite of what the > called H inside H reported. No that is not true. D never gets to the point where it can possibly do the opposite of whatever H reports. *D correctly simulated by H cannot possibly reach past its own line 03* Thanks for your help. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer