Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory,sci.logic Subject: Re: Can you see that D correctly simulated by H remains stuck in recursive simulation? Date: Fri, 24 May 2024 16:39:03 -0500 Organization: A noiseless patient Spider Lines: 83 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 24 May 2024 23:39:04 +0200 (CEST) Injection-Info: dont-email.me; posting-host="853a48eea7a3e841565c364baea8e5bf"; logging-data="2635919"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18npji76RssBktevh0ymO8z" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:wTZQHJ6uaJ5xxJ3mzOU0fcBWlqs= In-Reply-To: Content-Language: en-US Bytes: 4748 On 5/24/2024 4:03 PM, Richard Damon wrote: > On 5/24/24 4:01 PM, olcott wrote: >> On 5/24/2024 12:25 PM, Richard Damon wrote: >>> On 5/24/24 1:10 PM, olcott wrote: >>>> On 5/24/2024 2:37 AM, Fred. Zwarts wrote: >>>>> Op 23.mei.2024 om 19:04 schreef olcott: >>>>>> 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       } >>>>>> >>>>>> The above template refers to an infinite set of H/D pairs where D is >>>>>> correctly simulated by pure function H. This was done because many >>>>>> reviewers used the shell game ploy to endlessly switch which H/D pair >>>>>> was being referred to. >>>>>> >>>>>> *Correct Simulation Defined* >>>>>>     This is provided because every reviewer had a different notion of >>>>>>     correct simulation that diverges from this notion. >>>>>> >>>>>>     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. >>>>>> >>>>>> *Execution Trace* >>>>>>     Line 11: main() invokes H(D,D); H(D,D) simulates lines 01, 02, >>>>>> and 03 >>>>>>     of D. This invokes H(D,D) again to repeat the process in endless >>>>>>     recursive simulation. >>>>>> >>>>> >>>>> Of course this depends very much on the exact meaning of 'correct >>>>> simulation', or 'correctly emulating'. >>>> >>>> Not when these are defined above. >>>> >>>>> E.g., take the call to H(p, p). If H recognizes that it is a call >>>>> to a H with the same algorithm as is it using itself, and it knows >>>>> that itself returns a certain integer value K, than it can be >>>>> argued that it is a correct emulation to substitute the call to H >>>>> with this integer value K, which is assigned to Halt_Status. Then >>>>> the simulation of D can proceed to line 04. >>>>> What we need is an exact definition of 'correct simulation', in this >>>> >>>> No, you simply need to pay complete attention to the fact that this >>>> has already been provided. >>>> >>>> I have been over the exact same issue with dozens and dozen of people >>>> though hundreds and hundreds of messages over two years. >>> >>> Excpet that we have two contradictory definitions present, >> >> Yes you have a definition of simulation where the x86 machine >> language of D is simulated incorrectly or in the wrong order. > > Nope. The UTM definition still simulates EVERY x86 machine language > instruction of D simulated correctly in the exact order. The added > requirement is that we look at a simulation that is never aborted. H is a pure function that always returns 56 at some point other than that H is isomorphic to a UTM. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer