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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!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 Subject: Re: Every D(D) simulated by H presents non-halting behavior to H ### Date: Wed, 15 May 2024 10:24:57 -0500 Organization: A noiseless patient Spider Lines: 124 Message-ID: References: <-5Gdnf-nQvstC6b7nZ2dnZfqnPadnZ2d@brightview.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 15 May 2024 17:24:59 +0200 (CEST) Injection-Info: dont-email.me; posting-host="0b1a5f306bf9a6832a28841b3fc547c1"; logging-data="1006436"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/cy9ZbM5xUY/wCPHCG0gIJ" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:y8KnZism7cKPFktO0p2TcOMk9m8= Content-Language: en-US In-Reply-To: Bytes: 5537 On 5/15/2024 3:18 AM, Mikko wrote: > On 2024-05-14 14:35:42 +0000, olcott said: > >> On 5/14/2024 4:52 AM, Mikko wrote: >>> On 2024-05-13 14:43:09 +0000, olcott said: >>> >>>> On 5/13/2024 4:14 AM, Mikko wrote: >>>>> On 2024-05-13 04:54:30 +0000, immibis said: >>>>> >>>>>> On 10/05/24 19:55, Alan Mackenzie wrote: >>>>>>> [ Followup-To: set ] >>>>>>> >>>>>>> In comp.theory olcott wrote: >>>>>>> >>>>>>> [ .... ] >>>>>>> >>>>>>> I've tried out your much spammed code on GCC (see below).  It is >>>>>>> clear >>>>>>> you have never built or run this code, which ironically can't >>>>>>> reach Line >>>>>>> 06.  It can't even reach line 00. >>>>>>> >>>>>>>> Richard tried to get away with D never simulated by H as an example >>>>>>>> of D simulated by H: >>>>>>> >>>>>>>> Message-ID: >>>>>>>> On 5/1/2024 7:28 PM, Richard Damon wrote: >>>>>>> >>>>>>>> *That people say they know I am wrong yet will not show the >>>>>>>> detailed* >>>>>>>> *steps of how I am wrong indicates that they are probably liars* >>>>>>> >>>>>>> You have said, or at least implied that your code fragment is >>>>>>> runnable. >>>>>>> I think you are the liar, here. >>>>>>> >>>>>>>> 00 int H(ptr x, ptr x)  // ptr is pointer to int function >>>>>>>> 01 int D(ptr x) >>>>>>>> 02 { >>>>>>>> 03   int Halt_Status = H(x, x); >>>>>>>> 04   if (Halt_Status) >>>>>>>> 05     HERE: goto HERE; >>>>>>>> 06   return Halt_Status; >>>>>>>> 07 } >>>>>>>> 08 >>>>>>>> 09 int main() >>>>>>>> 10 { >>>>>>>> 11   H(D,D); >>>>>>>> 12 } >>>>>>> >>>>>>> >>>>>>> .  These are the diagnostics generated by GCC: >>>>>>> >>>>>> And the halting problem is about Turing machines, anyway. >>>>> >>>>> Not necessarily. The same question can be asked about different >>>>> machines. >>>>> The restriction to Turing machines is just one way to ensure that the >>>>> problem is well defined. >>>>> >>>> >>>> Well put. All computable functions even if written in C. >>> >>> You still must ensure that the problem is well defined. With C there is >>> the problem that conforming C programs often fail to be strictly >>> conforming. >>> If a program is not strictly conforming it may be interpreted as halting >>> by some implementation and non-halting or incorrect by another. >>> >> >> 00 int H(ptr x, ptr x)  // ptr is pointer to int function >> 01 int D(ptr x) >> 02 { >> 03   int Halt_Status = H(x, x); >> 04   if (Halt_Status) >> 05     HERE: goto HERE; >> 06   return Halt_Status; >> 07 } >> 08 >> 09 int main() >> 10 { >> 11   H(D,D); >> 12 } >> >> One can correctly determine that every D simulated by H >> never reaches past its own line 03. > > That is not strictly conforming and hardly conforming at all. > What trivial syntactic error that has no effect what-so-ever on the semantics do you believe remains? A missing semi-colon? typedef int (*ptr)(); // ptr is pointer to int function 00 int H(ptr x, ptr x); 01 int D(ptr x) 02 { 03 int Halt_Status = H(x, x); 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 } The example must be simple enough so that people unfamiliar with C will not be overwhelmed by things such as: typedef int (*ptr)(); a return value of 0 from main() also might be a little confusing. I am trying to fit the essence of my proof on a single page. Any H/D pair matching the above template where D(D) is simulated by the same H(D,D) that it calls cannot possibly reach past its own line 03. This is a simple software engineering verified fact. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer