Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory Subject: Re: Incorrect requirements --- Computing the mapping from the input to HHH(DD) Date: Fri, 9 May 2025 10:57:00 -0500 Organization: A noiseless patient Spider Lines: 63 Message-ID: References: <87msbmeo3b.fsf@nosuchdomain.example.com> <87a57mek8r.fsf@nosuchdomain.example.com> <87seled0zy.fsf@nosuchdomain.example.com> <2b99f70ab35ec939ead52ef88135a2f39e141ad2@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 09 May 2025 17:57:00 +0200 (CEST) Injection-Info: dont-email.me; posting-host="b8226b0a928845ead4a9adb4b3b34c7d"; logging-data="3003413"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+13uHFDCDH8svxAZ3MuBaK" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:MsjOoRV+EeV0lcn3nU8y9ZNqemY= Content-Language: en-US X-Antivirus-Status: Clean In-Reply-To: X-Antivirus: Norton (VPS 250509-2, 5/9/2025), Outbound message On 5/9/2025 10:47 AM, joes wrote: > Am Fri, 09 May 2025 10:08:40 -0500 schrieb olcott: >> On 5/9/2025 4:48 AM, joes wrote: >>> Am Thu, 08 May 2025 22:34:35 -0500 schrieb olcott: >>>> On 5/8/2025 10:14 PM, Mike Terry wrote: >>>>> On 09/05/2025 03:13, olcott wrote: >>>>>> On 5/8/2025 8:30 PM, Keith Thompson wrote: >>>>>>> olcott writes: >>>>>>>> On 5/8/2025 6:49 PM, Keith Thompson wrote: >>>>>>>>> olcott writes: >>> >>>>> His simulation is in fact a single-stepped x86 instruction >>>>> simulation, where the stepping of each x86 instruction is under the >>>>> HHH's control. HHH can continue stepping the simulation until its >>>>> target returns, in which case the situation is logically just like >>>>> direct call, as you have described.  Or HHH could step just 3 x86 >>>>> instructions (say) and then decide to return (aka "abort" its >>>>> simulation).  Let's call that / >>>>> partial/ simulation in contrast with /full/ simulation which you've >>>>> been supposing. >>>> A full simulation of infinite recursion? >>>> I am only doing one tiny idea at a time here. >>> Yeah, so not a full simulation. >> Didn't you know this? >> It is incorrect for a simulating termination analyzer to do a full >> simulation of a non-halting input. >> >>>>>>> In practice, the program will likely crash due to a stack overflow, >>>>>>> unless the compiler implements tail-call optimization, in which >>>>>>> case the program might just run forever -- which also means the >>>>>>> unnecessary return statement will never be reached. >>>>>> Yes you totally have this correctly. >>>>>> None of the dozens of comp.theory people could ever achieve that >>>>>> level of understanding even after three years. That is why I needed >>>>>> to post on comp.lang.c. >>>>> Everybody on comp.theory understands this much. >>>> No one here ever agreed that when 1 or more instructions of DDD are >>>> correctly simulated by HHH that DDD cannot possibly reach its own >>>> "return" instruction. >>> That's wrong as written. HHH cannot simulate DDD returning in a finite >>> number of instructions, it takes infinitely many. >> HHH can simulate 1 or more instructions of DDD, >> this is not actually logically impossible. >> When HHH does correctly simulate 1 or more instructions of DDD then DDD >> never reaches its "return statement" final halt state. > HHH simulates DDD returning only in an infinite number of steps. > void DDD() { HHH(DDD); return; } When 1 or more statements of DDD are correctly simulated by HHH then this correctly simulated DDD cannot possibly reach its own “return statement”. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer