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 16:56:51 -0500 Organization: A noiseless patient Spider Lines: 65 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sat, 05 Apr 2025 23:56:52 +0200 (CEST) Injection-Info: dont-email.me; posting-host="e43e7c1591a16e2ce23fcf8c89544fe3"; logging-data="3500793"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18Oh31KP6mtC4I/RpFGyMQ9" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:nLA0nM3wMkoJmL/YOpov22NUzi0= In-Reply-To: X-Antivirus: Norton (VPS 250405-6, 4/5/2025), Outbound message Content-Language: en-US X-Antivirus-Status: Clean Bytes: 4099 On 4/5/2025 4:48 PM, dbush wrote: > On 4/5/2025 5:40 PM, olcott wrote: >> On 4/5/2025 4:14 PM, dbush wrote: >>> On 4/5/2025 3:01 PM, olcott wrote: >>>> On 4/5/2025 1:45 PM, Richard Heathfield wrote: >>>>> On 05/04/2025 19:11, olcott wrote: >>>>>> On 4/5/2025 11:25 AM, dbush wrote: >>>> >>>>>>> On 4/5/2025 11:59 AM, olcott wrote:>>>> >>>>>>>> Introduction to the Theory of Computation 3rd Edition >>>>>>>> by Michael Sipser (Author) (best selling textbook) >>>>>>>> >>>>>>>> >>>>>>> 10/13/2022> >>>>>>>>      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. >>>>>>>> >>>>>>> 10/13/2022> >>>>>>> >>>>>>> But not what you think he agreed to: >>>>>>> >>>>>>> >>>> >>>> void DDD() >>>> { >>>>    HHH(DDD); >>>>    return; >>>> } >>>> >>>>>> >>>>>> You have to show that by showing the details of how >>>>>> what he agreed to is not accurately paraphrased by >>>>>> *Simulating termination analyzer Principle* >>>>> >>>>> No, you have to show firstly that your H determines anything at all >>>>> about D's behaviour. >>>> >>>> First of all it is the concrete DDD and the hypothetical HHH. >>> >>> Category error.  The algorithm DDD is not fully specified if the code >>> of the function HHH and everything it calls explicitly spelled out, >>> as all of that is the code under test. >> >> DDD meets the spec of the >> *Simulating termination analyzer Principle* >> as long as HHH emulates enough steps of DDD >> to see that it must stop simulating DDD. >> > > And as such is unrelated to the halting problem, as the halting problem > is about algorithms, and DDD as you've defined it is not an algorithm: > OK great we are making progress. You agree that the specified DDD and a hypothetical HHH could meet the *Simulating termination analyzer Principle* -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer