Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Richard Heathfield Newsgroups: comp.theory Subject: Re: Incorrect requirements --- Computing the mapping from the input to HHH(DD) Date: Fri, 9 May 2025 22:40:53 +0100 Organization: Fix this later Lines: 55 Message-ID: References: <87msbmeo3b.fsf@nosuchdomain.example.com> <87ecwyekg2.fsf@nosuchdomain.example.com> <87bjs2cyj6.fsf@nosuchdomain.example.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 09 May 2025 23:40:53 +0200 (CEST) Injection-Info: dont-email.me; posting-host="2b573b17a97b3b771864cdd7a1499e84"; logging-data="3211084"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18mpLMuYif/N8Y499CXDM+Gk+wvv/Wgwz9qzj8kd7Iydg==" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:0uLx1sRGgyAlqDu7yeHesFlaVZE= Content-Language: en-GB In-Reply-To: Bytes: 3690 On 09/05/2025 21:15, olcott wrote: > On 5/9/2025 3:07 PM, Richard Heathfield wrote: >> On 09/05/2025 20:46, olcott wrote: >>> We have not begun to get into any of those points. >>> We are only asking can DDD correctly simulated >>> by any HHH that can exist ever reach its own >>> "return" instruction. >> >> DDD can't be correctly simulated by itself (which is >> effectively what you're trying to do when you fire up the >> simulation from inside DDD). >> > > How the Hell did you twist my words to say that? I haven't touched your words. What I have done is to observe that DDD's /only/ action is to call a simulator. Since DDD isn't itself a simulator, there is nothing to simulate except a call to a simulator. It's recursion without a base case - a rookie error. HHH cannot successfully complete its task, because it never regains control after the first recursion. To return, it must abort the simulation, which means the simulation fails. > > 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”. On what grounds can you persuade an extraordinarily sceptical readership that HHH 'correctly simulated' DDD? There are only two possibilities: (a) HHH aborts the simulation prematurely, or (b) it doesn't. If (a), the simulation fails to 'play' DDD correctly. If (b), the simulation fails to arrive at a decision. -- Richard Heathfield Email: rjh at cpax dot org dot uk "Usenet is a strange place" - dmr 29 July 1999 Sig line 4 vacant - apply within