Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.lang.c Subject: Re: DD simulated by HHH cannot possibly halt (Halting Problem) Date: Sat, 5 Apr 2025 19:52:51 -0500 Organization: A noiseless patient Spider Lines: 57 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 06 Apr 2025 02:52:52 +0200 (CEST) Injection-Info: dont-email.me; posting-host="9b6a58fda5364b319cd96985a9bb23a0"; logging-data="3835999"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19ecqHzklxuEiQW35nN44/Z" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:s6HltnkE86Vlyq6/5iZvEfg4/24= In-Reply-To: X-Antivirus-Status: Clean X-Antivirus: Norton (VPS 250405-6, 4/5/2025), Outbound message Content-Language: en-US Bytes: 3931 On 4/5/2025 6:15 PM, dbush wrote: > On 4/5/2025 7:07 PM, olcott wrote: >> On 4/5/2025 4:59 PM, dbush wrote: >>> On 4/5/2025 5:56 PM, olcott wrote: >>>> >>>> OK great we are making progress. >>>> You agree that the specified DDD and a >>>> hypothetical HHH could meet the >>>> *Simulating termination analyzer Principle* >>>> >>> >>> Which you will be unable to link back to the halting problem: >>> >>> >>> Given any algorithm (i.e. a fixed immutable sequence of instructions) >>> X described as with input Y: >>> >>> A solution to the halting problem is an algorithm H that computes the >>> following mapping: >>> >>> (,Y) maps to 1 if and only if X(Y) halts when executed directly >>> (,Y) maps to 0 if and only if X(Y) does not halt when executed >>> directly >>> >> >> *Yet may be able to link back to this* >> >> >>      If simulating halt decider H correctly simulates its input D >>      until H correctly determines that its simulated D would never >>      stop running unless aborted then >> >>      H can abort its simulation of D and correctly report that D >>      specifies a non-halting sequence of configurations. >> >> > > Which is not what you think he agreed to: > > > On Monday, March 6, 2023 at 2:41:27 PM UTC-5, Ben Bacarisse wrote: > > I exchanged emails with him about this. He does not agree with anything > > substantive that PO has written. I won't quote him, as I don't have > > permission, but he was, let's say... forthright, in his reply to me. > > > Yet may be exactly what he agreed to: *Simulating termination analyzer Principle* It is always correct for any simulating termination analyzer to stop simulating and reject any input that would otherwise prevent its own termination. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer