Path: ...!weretis.net!feeder9.news.weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory,sci.logic Subject: Re: D correctly simulated by pure function H cannot possibly reach its, own line 06 --- Date: Sun, 26 May 2024 12:01:25 -0500 Organization: A noiseless patient Spider Lines: 48 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 26 May 2024 19:01:26 +0200 (CEST) Injection-Info: dont-email.me; posting-host="b67ec24a85de95a55e6b4d0cc81926c3"; logging-data="3670723"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19A3KEPy1taeQKmPs8k37aj" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:DggFzCgiGr+vTG6FHnkuXuCSldY= In-Reply-To: Content-Language: en-US Bytes: 4017 On 5/26/2024 11:31 AM, Richard Damon wrote: > On 5/26/24 10:13 AM, olcott wrote: >> On 5/26/2024 6:43 AM, Richard Damon wrote: >> >> 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       } >> >> >>> Because, as I have said, the answer and reasoning changes depending >>> on what you acknowledged are the implications of your stipulations. >>> For instance, if your actual understanding of being a "Pure Function" >>> is that the program is the equivalent of a Turing Machine, then we >>> need to add a strictness to the definition that isn't normally used >>> for just "Pure Functions", like accessing value of registers like the >>> program counter or stack pointer might not be allowed in some cases. >>> (which breaks you H). >>> >> >> Since we can see (and you already agreed) that D correctly simulated >> by pure simulator H remains stuck in infinite recursive simulation then >> we also know that D never reaches its own line 06 and halts in less >> than an infinite number of correctly simulated steps. > > But it depends on what H actually does, which you refuse to agree to. > When I specify that D is correctly simulated by pure function H, that means that H is a pure simulator that stops simulating D after some finite number of correctly simulated steps. There is absolutely nothing else that needs to be known about H besides this. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer