Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory Subject: Re: DD specifies non-terminating behavior to HHH --- RECURSIVE CHAIN --- Saving Democracy Date: Sat, 22 Feb 2025 12:54:48 -0600 Organization: A noiseless patient Spider Lines: 122 Message-ID: References: <855e571c6668207809e1eb67138de6af48d164fa@i2pn2.org> <8fa176d46bf5b8c36def9e32ced67a1a3f81bae1@i2pn2.org> <2e999502c40f736a3f3579d23bdb2b42dc74e897@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sat, 22 Feb 2025 19:54:50 +0100 (CET) Injection-Info: dont-email.me; posting-host="ef107bbb25b24353ee4244c5f8345170"; logging-data="92421"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18xMZXz+lNQV5a7Yr0qYdEO" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:L6WpHaaQBS0tvo2gEw9UpnLsjlc= X-Antivirus: Norton (VPS 250222-4, 2/22/2025), Outbound message In-Reply-To: X-Antivirus-Status: Clean Content-Language: en-US On 2/22/2025 12:21 PM, dbush wrote: > On 2/22/2025 1:02 PM, olcott wrote: >> On 2/22/2025 11:10 AM, dbush wrote: >>> On 2/22/2025 11:43 AM, olcott wrote: >>>> On 2/22/2025 5:01 AM, joes wrote: >>>>> Am Fri, 21 Feb 2025 21:55:32 -0600 schrieb olcott: >>>>>> On 2/20/2025 4:00 AM, joes wrote: >>>> >>>> >>>>>>> Not even the variable Root in line 502 of Halt7.c? >>>>>> https://github.com/plolcott/x86utm/blob/master/Halt7.c You are not >>>>>> even >>>>>> in the correct function. >>>>> 1059 >>>>> >>>> >>>> Unless we go through a 100% precise sequence of steps >>>> my reviewers will always consistently dodge the point >>>> as they have done for several years. >>>> >>>> typedef void (*ptr)(); >>>> int HHH(ptr P); >>>> >>>> int DD() >>>> { >>>>    int Halt_Status = HHH(DD); >>>>    if (Halt_Status) >>>>      HERE: goto HERE; >>>>    return Halt_Status; >>>> } >>>> >>>> int main() >>>> { >>>>    HHH(DD); >>>> } >>>> >>>> The first point is DD correctly simulated by HHH cannot >>>> possibly terminate normally by reaching its own "return" >>>> instruction. >>> >>> In other words, if the code of HHH is replaced with an unconditional >>> simulator then it can be shown that DD is non-halting and therefore >>> HHH(DD)==0 is correct. >>> >> >> Wow finally someone that totally gets it. >> >>> Let's test that on another case. >>> >> 01 int F(int i) >> 02 { >> 03      if (i<10) { >> 04          return 0; >> 05      } else { >> 06          return F(i+1); >> 07      } >> 08 } >> 09 >> 10 int no_numbers_greater_than_10() >> 11 { >> 12      return F(0); >> 13 } >> 14 >> 15 int main() >> 16 { >> 17   no_numbers_greater_than_10(); >> 18   return 0; >> 19 } > > Actually, let's update main: > > int main() > { >    F((int)no_numbers_greater_than_10); >    return 0; > } > >>> >>> The function no_numbers_greater_than_10() checks if any natural >>> number exists that is greater than 10.  It does this by checking all >>> natural numbers one at a time.  If one such number exists it halts >>> and return 0.   If no such number exists, it will run forever as no >>> such number will satisfy the condition. >>> >> >> Your code is incomplete. I added main() with line numbers. >> >>> We can see that no_numbers_greater_than_10 correctly simulated by F >>> cannot possibly terminate normal by reaching its own "return" >>> instruction.  This means that F correctly reports that >>> no_numbers_greater_than_10 is non-halting.  It further means, since >>> no_numbers_greater_than_10  doesn't halt that there is no natural >>> number greater than 10. >>> >>> Agreed? >> >> Here the execution trace that I see: >> 15, 16, 17, 10, 11, 12, 01, 02, 03, 04, 12, 18, 19 >> > > Just as you say we're not talking about the direct execution of DD, > we're also not talking about the direct execution of > no_numbers_greater_than_10.  We're talking about > no_numbers_greater_than_10 correctly simulated by F. > > It's a verified fact that no_numbers_greater_than_10 correctly simulated > by F cannot possibly return so F(no_numbers_greater_than_10) is correct > to report non-halting, which means that there is no natural number > greater than 10. > > Agreed? > Leaving out main() made this difficult. We can assume that the address of no_numbers_greater_than_10 > 10. This will emulate no_numbers_greater_than_10 at incorrect byte offsets causing it to crash. This may or may not make F crash depending on how robust its emulator is. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer