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Path: ...!weretis.net!feeder9.news.weretis.net!i2pn.org!i2pn2.org!.POSTED!not-for-mail From: Richard Damon <richard@damon-family.org> Newsgroups: comp.theory,sci.logic Subject: Re: Every D(D) is correctly simulated by H Date: Sun, 19 May 2024 15:49:53 -0400 Organization: i2pn2 (i2pn.org) Message-ID: <v2dl51$1g2n9$12@i2pn2.org> References: <v18e32$1vbql$1@dont-email.me> <v1dtdv$3dqg4$1@dont-email.me> <v1du2i$3dt7u$1@dont-email.me> <v1fetd$3s7jo$1@dont-email.me> <v1ft42$3vdau$2@dont-email.me> <-5Gdnf-nQvstC6b7nZ2dnZfqnPadnZ2d@brightview.co.uk> <v1gid8$4ilc$1@dont-email.me> <v1h9eu$9faf$1@dont-email.me> <v1iqli$nsva$1@dont-email.me> <v1ln3c$vfh$1@news.muc.de> <v1s6e6$397iq$2@dont-email.me> <v1slmi$3cjtp$1@dont-email.me> <v1t8tt$3gu9t$3@dont-email.me> <v1vc8j$3jmr$1@dont-email.me> <v1vsru$7eqc$1@dont-email.me> <v21r4i$otc2$2@dont-email.me> <v22k4b$umr4$1@dont-email.me> <v24oah$1h4u3$1@dont-email.me> <v256fc$1kais$1@dont-email.me> <v27d05$25ga0$1@dont-email.me> <v2838r$29rd7$1@dont-email.me> <v2a8th$2ps09$1@dont-email.me> <v2ahqc$2qvr9$1@dont-email.me> <v2cb5s$39fvg$1@dont-email.me> <v2crk0$3cifp$1@dont-email.me> <v2cvuo$3dfkm$1@dont-email.me> <v2d0qm$3ddo5$3@dont-email.me> <v2dc7a$1g2n9$5@i2pn2.org> <v2dffn$3gjtv$1@dont-email.me> <v2diom$1g2n8$3@i2pn2.org> <v2djtt$3hgb1$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 19 May 2024 19:49:53 -0000 (UTC) Injection-Info: i2pn2.org; logging-data="1575657"; 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: <v2djtt$3hgb1$1@dont-email.me> Content-Language: en-US Bytes: 10735 Lines: 248 On 5/19/24 3:29 PM, olcott wrote: > On 5/19/2024 2:09 PM, Richard Damon wrote: >> On 5/19/24 2:13 PM, olcott wrote: >>> On 5/19/2024 12:17 PM, Richard Damon wrote: >>>> On 5/19/24 10:03 AM, olcott wrote: >>>>> On 5/19/2024 8:48 AM, Mikko wrote: >>>>>> On 2024-05-19 12:34:08 +0000, olcott said: >>>>>> >>>>>>> On 5/19/2024 2:53 AM, Mikko wrote: >>>>>>>> On 2024-05-18 15:34:36 +0000, James Kuyper said: >>>>>>>> >>>>>>>>> On 5/18/24 09:02, Mikko wrote: >>>>>>>>>> On 2024-05-17 17:14:01 +0000, olcott said: >>>>>>>>> >>>>>>>>> I recommend ignoring olcott - nothing good ever comes from paying >>>>>>>>> attention to him. >>>>>>>>> >>>>>>>>>>> On 5/17/2024 5:53 AM, Mikko wrote: >>>>>>>>>>>> On 2024-05-16 14:50:19 +0000, olcott said: >>>>>>>>>>>> >>>>>>>>>>>>> On 5/16/2024 5:48 AM, Mikko wrote: >>>>>>>>>>>>>> On 2024-05-15 15:24:57 +0000, olcott said: >>>>>>>>> ... >>>>>>>>>>>>>>> typedef int (*ptr)(); // ptr is pointer to int function >>>>>>>>>>>>>>> 00 int H(ptr x, ptr x); >>>>>>>>>>>>>>> 01 int D(ptr x) >>>>>>>>>>>>>>> 02 { >>>>>>>>>>>>>>> 03 int Halt_Status = H(x, x); >>>>>>>>>>>>>>> 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 } >>>>>>>>>>>>>> >>>>>>>>>>>>>> Can you find any compiler that is liberal enough to accept >>>>>>>>>>>>>> that? >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> It has been fully operational code under Windows and >>>>>>>>>>>>> Linux for two years. >>>>>>>>>>>> >>>>>>>>>>>> If your compiler does not reject that program it is not a >>>>>>>>>>>> conforming >>>>>>>>>>>> C compiler. The semantics according to C standard is that a >>>>>>>>>>>> diagnostic >>>>>>>>>>>> message must be given. The standard does not specify what >>>>>>>>>>>> happens if >>>>>>>>>>>> you execute that program anyway. >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> It is not nit picky syntax that is the issue here. >>>>>>>>>>> The SEMANTICS OF THE C PROGRAMMING LANGUAGE SPECIFIES >>>>>>>>>>> >>>>>>>>>>> No D simulated correctly by any H of every H/D pair specified >>>>>>>>>>> by the above template ever reaches its own line 06 and halts. >>>>>>>>>> >>>>>>>>>> The standard allows that an program is executed but does not >>>>>>>>>> specify what happens when an invalid program is executed. >>>>>>>>> >>>>>>>>> You've cross-posted this to comp.lang.c after a long-running >>>>>>>>> discussion >>>>>>>>> solely on comp.theory. Presumably you're doing that because you >>>>>>>>> want >>>>>>>>> some discussion about what the standard says about this code. >>>>>>>>> For the >>>>>>>>> sake of those of us who have not been following that discussion on >>>>>>>>> comp.theory, could you please identify what it is that you >>>>>>>>> think renders >>>>>>>>> this code invalid? Offhand, I don't see anything wrong with it, >>>>>>>>> but I'm >>>>>>>>> far more reliable when I say "I see an error" than when I say >>>>>>>>> "I don't >>>>>>>>> see an error". >>>>>>>>> >>>>>>>>> >>>>>>>>>>> Fully operational software that runs under Widows and Linux >>>>>>>>>>> proves that the above is true EMPIRICALLY. >>>>>>>>>> >>>>>>>>>> No, it does not. As the program is not strictly comforming >>>>>>>>>> and uses a non-standard extension some implementation may >>>>>>>>>> execute it differently or refuse to execute. >>>>>>>>> >>>>>>>>> Which non-standard extension does it use? >>>>>>>> >>>>>>>> The main question is whether both arguments of H on the line 00 >>>>>>>> can have >>>>>>>> the same name. >>>>>>> >>>>>>> That was a typo that I did not believe when told because so may >>>>>>> people >>>>>>> continue to lie about the behavior of D correctly simulated by H. >>>>>> >>>>>> How does the D that is correctly simulated by H different from any >>>>>> D that is incorrectly simulated by H nor not simulated by H? >>>>>> >>>>> >>>>> typedef int (*ptr)(); // ptr is pointer to int function >>>>> 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 } >>>>> >>>>> In the above case a simulator is an x86 emulator that correctly >>>>> emulates at least one of the x86 instructions of D in the order >>>>> specified by the x86 instructions of D. >>>>> >>>>> This may include correctly emulating the x86 instructions of H >>>>> in the order specified by the x86 instructions of H thus calling >>>>> H(D,D) in recursive simulation. >>>>> >>>> >>>> Which has been proven incorrect. >>> >>> *Quoted from page 4 of the paper linked below* >>> // Simplified Linz Ĥ (Linz:1990:319) >>> // Strachey(1965) CPL translated to C >>> void P(u32 x) >>> { >>> if (H(x, x))HERE: >>> goto HERE; >>> } >>> >>> int main() >>> { >>> Output("Input_Halts = ", H((u32)P, (u32)P)); >>> } >>> >>> That P is correctly simulated by H is proven by the fact that >>> every assembly language instruction of P is correctly simulated >>> by H in the order specified by the x86 assembly language of P >>> even when H correctly simulates itself simulating P. >>> >>> All of the details of this (except the 354 page execution >>> trace of H) are shown on pages 4-5 of the following paper. >> >> Which of course, will have the details of what H did wrong. >> >>> >>> *Halting problem undecidability and infinitely nested simulation* >>> https://www.researchgate.net/publication/351947980_Halting_problem_undecidability_and_infinitely_nested_simulation >>> >>> >> >> So, which instruction CORRECTLY SIMULATED allows H to CORRECTLY >> DETERMINE that its input is non-halting? >> > ========== REMAINDER OF ARTICLE TRUNCATED ==========