Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: wij Newsgroups: comp.lang.c++ Subject: Re: D correctly simulated by H remains stuck in recursive simulation [good attempt] Date: Thu, 23 May 2024 05:35:31 +0800 Organization: A noiseless patient Spider Lines: 144 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" Content-Transfer-Encoding: quoted-printable Injection-Date: Wed, 22 May 2024 23:35:32 +0200 (CEST) Injection-Info: dont-email.me; posting-host="155d000b7a3ae65bf9b4d0dc43a179b9"; logging-data="1438194"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1//wBC1h1djxodSJAlqtiDj" User-Agent: Evolution 3.50.2 (3.50.2-1.fc39) Cancel-Lock: sha1:PCTxH1b5I8VWBSULyttoCgrcOvw= In-Reply-To: Bytes: 7777 On Wed, 2024-05-22 at 16:26 -0500, olcott wrote: > 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: > > > > > > > >=20 > > > > > > > > > > You're neither asking about a C- or C++ problem. > > > > > > > > > > So use a proper newsgroup. > > > > > > > > > >=20 > > > > > > > > >=20 > > > > > > > > > There is no other group that knows enough about the seman= tics of the > > > > > > > > > C programming language and there is no other group still = alive that > > > > > > > > > knows enough about the semantics of programming languages= .. > > > > > > > >=20 > > > > > > > > Then FFS take it to Reddit, where there are a myriad thrivi= ng forums, > > > > > > > > rather than a dying usenet group populated by a few aging r= egulars. > > > > > > > >=20 > > > > > > > >=20 > > > > > > >=20 > > > > > > > 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 qu= estion. > > > > > > >=20 > > > > > >=20 > > > > > > The /only/ reason you are not banned here is because unmoderate= d Usenet > > > > > > groups cannot ban people. > > > > > >=20 > > > > > > You post obsessively in many places, and face nothing but rejec= tion, > > > > > > ridicule, and banning.=C2=A0 Has it ever occurred to you to loo= k for the > > > > > > common factor here?=C2=A0 It is /you/, and the posts you make.= =C2=A0 If you truly > > > > > > want to make progress on your bizarre ideas, you are going to h= ave to > > > > > > re-think your strategy - it is entirely obvious to everyone tha= t you > > > > > > will not get the answers you are asking for here or anywhere el= se with > > > > > > your current posting style. > > > > > >=20 > > > > > >=20 > > > > >=20 > > > > > *On the other hand people could simply answer my question* > > > > > *I only repeat it until it is answered* > > > > >=20 > > > > > For every H/D pair matching the following template where > > > > > H is a pure function: > > > > >=20 > > > > > Does any D correctly simulated by H reach its own line 06 and > > > > > halt or does the fact that D remains stuck in recursive simulatio= n > > > > > prevent that? > > > > >=20 > > > > > typedef int (*ptr)();=C2=A0 // ptr is pointer to int function in = C > > > > > 00=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 int H(ptr p, ptr i); > > > > > 01=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 int D(ptr p) > > > > > 02=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 { > > > > > 03=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 int Halt_Statu= s =3D H(p, p); > > > > > 04=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (Halt_Statu= s) > > > > > 05=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 HE= RE: goto HERE; > > > > > 06=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return Halt_St= atus; > > > > > 07=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } > > > > > 08 > > > > > 09=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 int main() > > > > > 10=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 { > > > > > 11=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 H(D,D); > > > > > 12=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 return 0; > > > > > 13=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } > > > > >=20 > > > > > 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 > > > > >=20 > > > > > 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. > > > > >=20 > > > > > This provides the basis for simulating termination analyzer H to > > > > > correctly determine that the halting problem's counter-example > > > > > input D cannot possibly halt. > > > > >=20 > > > >=20 > > > > If H is truly a simulator, its function is expected to be equivalen= t to: > > > >=20 > > > > int H(ptr x, ptr y) { > > > > =C2=A0=C2=A0 x(y); > > > > =C2=A0=C2=A0 return __WHATEVER; > > > > } > > > >=20 > > > > The H(D,D) can never halt. > > > >=20 > > > >=20 > > >=20 > > > Finally someone took 30 seconds to answer, thanks! > > > *The actual question was slightly different in a very crucial way* > > >=20 > > > 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 > > >=20 > > > 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. > >=20 > > Correct. H will be stuck in the recursive simulations. > >=20 > > > *In other words even when H(D,D) terminates normally D* > > > *correctly simulated by H cannot possibly terminate normally* > >=20 > > Correct. Because D is programmed to behave the opposite of what the > > called H inside H reported. >=20 > No that is not true. D never gets to the point where it can possibly > do the opposite of whatever H reports. >=20 > *D correctly simulated by H cannot possibly reach past its own line 03* > Thanks for your help. >=20 Correct. I was responding to "*In other words even when H(D,D) terminates normally..= .."