Path: ...!eternal-september.org!feeder3.eternal-september.org!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: Sun, 23 Feb 2025 23:01:47 -0600 Organization: A noiseless patient Spider Lines: 226 Message-ID: References: <2e999502c40f736a3f3579d23bdb2b42dc74e897@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 24 Feb 2025 06:01:48 +0100 (CET) Injection-Info: dont-email.me; posting-host="ad958933c7b8d1278b7f2c2f3e804b36"; logging-data="978892"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19R2OhHjYl7mIAi50rAaBy/" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:cw7E/pNUYeNjwTPOZXuJoJxJO8k= X-Antivirus-Status: Clean Content-Language: en-US In-Reply-To: X-Antivirus: Norton (VPS 250223-4, 2/23/2025), Outbound message Bytes: 11955 On 2/23/2025 10:45 PM, dbush wrote: > On 2/23/2025 11:42 PM, olcott wrote: >> On 2/23/2025 10:09 PM, dbush wrote: >>> On 2/23/2025 10:20 PM, olcott wrote: >>>> On 2/23/2025 9:15 PM, dbush wrote: >>>>> On 2/23/2025 9:04 PM, olcott wrote: >>>>>> On 2/23/2025 7:22 PM, dbush wrote: >>>>>>> On 2/23/2025 8:13 PM, olcott wrote: >>>>>>>> On 2/23/2025 6:15 PM, dbush wrote: >>>>>>>>> On 2/23/2025 7:10 PM, olcott wrote: >>>>>>>>>> On 2/23/2025 11:57 AM, dbush wrote: >>>>>>>>>>> On 2/23/2025 12:30 PM, olcott wrote: >>>>>>>>>>>> On 2/22/2025 8:34 PM, dbush wrote: >>>>>>>>>>>>> On 2/22/2025 7:33 PM, olcott wrote: >>>>>>>>>>>>>> On 2/22/2025 4:59 PM, dbush wrote: >>>>>>>>>>>>>>> On 2/22/2025 5:53 PM, olcott wrote: >>>>>>>>>>>>>>>> On 2/22/2025 2:59 PM, dbush wrote: >>>>>>>>>>>>>>>>> On 2/22/2025 3:53 PM, olcott wrote: >>>>>>>>>>>>>>>>>> On 2/22/2025 2:09 PM, dbush wrote: >>>>>>>>>>>>>>>>>>> On 2/22/2025 3:03 PM, olcott wrote: >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> 01 int F(int i) >>>>>>>>>>>>>>>>>> 02 { >>>>>>>>>>>>>>>>>> 03   if (i > 10) >>>>>>>>>>>>>>>>>> 04     return 0; >>>>>>>>>>>>>>>>>> 05   else >>>>>>>>>>>>>>>>>> 06     return F(i+1); >>>>>>>>>>>>>>>>>> 07 } >>>>>>>>>>>>>>>>>> 08 >>>>>>>>>>>>>>>>>> 09 int no_numbers_greater_than_10() >>>>>>>>>>>>>>>>>> 10 { >>>>>>>>>>>>>>>>>> 11   return F(0); >>>>>>>>>>>>>>>>>> 12 } >>>>>>>>>>>>>>>>>> 13 >>>>>>>>>>>>>>>>>> 14 int main() >>>>>>>>>>>>>>>>>> 15 { >>>>>>>>>>>>>>>>>> 16   F((int)no_numbers_greater_than_10); >>>>>>>>>>>>>>>>>> 17   return 0; >>>>>>>>>>>>>>>>>> 18 } >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> So if the address of no_numbers_greater_than_10 is >>>>>>>>>>>>>>>>>>> greater than 10 then 0 is returned right away, >>>>>>>>>>>>>>>>>>> otherwise as most 10 recursive calls will be made >>>>>>>>>>>>>>>>>>> before the condition is matched and 0 is returned. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> This doesn't change the 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? >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> I think that you will find more bugs when you try to >>>>>>>>>>>>>>>>>> provide the line number by line number execution trace. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> #1 bug F never simulates anything. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> It is a verified fact that >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> F never simulates anything when i > 10. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Remember, you agreed that the behavior of X simulated by >>>>>>>>>>>>>>> Y is defined by replacing the code of Y with an >>>>>>>>>>>>>>> unconditional simulator and running Y(X): >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> 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: >>>>>>>>>>>>>>>  >>> 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. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> So the behavior of no_numbers_greater_than_10 simulated >>>>>>>>>>>>>>> by F is defined by replacing the code of F with an >>>>>>>>>>>>>>> unconditional simulated and running >>>>>>>>>>>>>>> F(no_numbers_greater_than_10). >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> The finite string input to F proves that there are no >>>>>>>>>>>>>>> instructions in no_numbers_greater_than_10 that can break >>>>>>>>>>>>>>> the recursive simulation. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Try to show how no_numbers_greater_than_10 correctly >>>>>>>>>>>>>>> simulated by F can possibly halt. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Then is ceases to be analogous to HHH(DD) because >>>>>>>>>>>>>> no_numbers_greater_than_10() always terminates normally >>>>>>>>>>>>>> by reaching its own "return" instruction. >>>>>>>>>>>>> >>>>>>>>>>>>> In other words, when we actually run >>>>>>>>>>>>> no_numbers_greater_than_10() it reaches its own "return" >>>>>>>>>>>>> instruction. >>>>>>>>>>>>> >>>>>>>>>>>>> That means we've now established that the direct execution >>>>>>>>>>>>> of a program (which includes all the functions it calls >>>>>>>>>>>>> UNMODIFIED) defines whether or not it halts. >>>>>>>>>>>>> >>>>>>>>>>>>> Likewise, when we actually run DD() unmodified it also >>>>>>>>>>>>> reaches its own "return" instruction. >>>>>>>>>>>>> >>>>>>>>>>>>> Therefore HHH(DD)==0 is wrong. >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> _DD() >>>>>>>>>>>> [00002133] 55         push ebp      ; housekeeping >>>>>>>>>>>> [00002134] 8bec       mov ebp,esp   ; housekeeping >>>>>>>>>>>> [00002136] 51         push ecx      ; make space for local >>>>>>>>>>>> [00002137] 6833210000 push 00002133 ; push DD >>>>>>>>>>>> [0000213c] e882f4ffff call 000015c3 ; call HHH(DD) >>>>>>>>>>>> [00002141] 83c404     add esp,+04 >>>>>>>>>>>> [00002144] 8945fc     mov [ebp-04],eax >>>>>>>>>>>> [00002147] 837dfc00   cmp dword [ebp-04],+00 >>>>>>>>>>>> [0000214b] 7402       jz 0000214f >>>>>>>>>>>> [0000214d] ebfe       jmp 0000214d >>>>>>>>>>>> [0000214f] 8b45fc     mov eax,[ebp-04] >>>>>>>>>>>> [00002152] 8be5       mov esp,ebp >>>>>>>>>>>> [00002154] 5d         pop ebp >>>>>>>>>>>> [00002155] c3         ret >>>>>>>>>>>> Size in bytes:(0035) [00002155] >>>>>>>>>>>> >>>>>>>>>>>> When DD is correctly simulated by HHH according to the behavior >>>>>>>>>>>> that the above machine code specifies then the call from DD >>>>>>>>>>>> to HHH(DD) cannot possibly return and this correctly simulated >>>>>>>>>>>> DD cannot possibly terminate  normally by reaching its own >>>>>>>>>>>> machine >>>>>>>>>>>> address 00002155. >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Similarly: >>>>>>>>>>> >>>>>>>>>>> 0000000000400534 : >>>>>>>>>>>    400534:    55                       push   %rbp >>>>>>>>>>>    400535:    48 89 e5                 mov    %rsp,%rbp >>>>>>>>>>>    400538:    b8 34 05 40 00           mov    $0x400534,%eax >>>>>>>>>>>    40053d:    48 89 c7                 mov    %rax,%rdi >>>>>>>>>>>    400540:    e8 a8 ff ff ff           callq  4004ed >>>>>>>>>>>    400545:    5d                       pop    %rbp >>>>>>>>>>>    400546:    c3                       retq >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> When no_numbers_greater_than_10 is correctly simulated by F >>>>>>>>>>> according to the behavior that the above machine code >>>>>>>>>>> specifies then the call from no_numbers_greater_than_10  to >>>>>>>>>>> F(no_numbers_greater_than_10) cannot possibly terminate >>>>>>>>>>> normally by reaching its own machine address 400545 >>>>>>>>>>> ========== REMAINDER OF ARTICLE TRUNCATED ==========