Path: ...!feeds.phibee-telecom.net!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory Subject: Re: Who here understands that the last paragraph is Necessarily true? Date: Fri, 19 Jul 2024 09:46:19 -0500 Organization: A noiseless patient Spider Lines: 148 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 19 Jul 2024 16:46:19 +0200 (CEST) Injection-Info: dont-email.me; posting-host="806954090dbe9e2c0be16c7a3e599476"; logging-data="3172337"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX197oiu2uz/zpRCIagjMB/V5" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:9Qjn5jEzRSgN9MRCzpjMVuwHEEo= Content-Language: en-US In-Reply-To: Bytes: 6493 On 7/19/2024 4:07 AM, Mikko wrote: > On 2024-07-17 13:30:07 +0000, olcott said: > >> On 7/17/2024 2:49 AM, Mikko wrote: >>> On 2024-07-16 14:20:09 +0000, olcott said: >>> >>>> On 7/16/2024 3:32 AM, Mikko wrote: >>>>> On 2024-07-15 13:26:22 +0000, olcott said: >>>>> >>>>>> On 7/15/2024 3:23 AM, Mikko wrote: >>>>>>> On 2024-07-14 14:38:31 +0000, olcott said: >>>>>>> >>>>>>>> On 7/14/2024 3:09 AM, Mikko wrote: >>>>>>>>> On 2024-07-13 20:15:56 +0000, olcott said: >>>>>>>>> >>>>>>>>>> typedef void (*ptr)(); >>>>>>>>>> int HHH(ptr P); >>>>>>>>>> >>>>>>>>>> void Infinite_Loop() >>>>>>>>>> { >>>>>>>>>>    HERE: goto HERE; >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> void Infinite_Recursion() >>>>>>>>>> { >>>>>>>>>>    Infinite_Recursion(); >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> void DDD() >>>>>>>>>> { >>>>>>>>>>    HHH(DDD); >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> int main() >>>>>>>>>> { >>>>>>>>>>    HHH(Infinite_Loop); >>>>>>>>>>    HHH(Infinite_Recursion); >>>>>>>>>>    HHH(DDD); >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> Any input that must be aborted to prevent the non >>>>>>>>>> termination of HHH necessarily specifies non-halting >>>>>>>>>> behavior or it would never need to be aborted. >>>>>>>>> >>>>>>>>> Everyone understands that DDD specifies a halting behaviour if >>>>>>>>> HHH(DDD) does, >>>>>>>> >>>>>>>> >>>>>>>> *You can comprehend this is a truism or fail to* >>>>>>>> *comprehend it disagreement is necessarily incorrect* >>>>>>>> Any input that must be aborted to prevent the non >>>>>>>> termination of HHH necessarily specifies non-halting >>>>>>>> behavior or it would never need to be aborted. >>>>>>>> >>>>>>>> Disagreeing with the above is analogous to disagreeing >>>>>>>> with arithmetic. >>>>>>> >>>>>>> That the input is aborted does not mean that the input must be >>>>>>> aborted. >>>>>> >>>>>> Weasel words. This is an axiom: >>>>>> Input XXX must be aborted to prevent the non-termination of HHH. >>>>> >>>>> That is not an acceptable axiom. That you are unable to prove that >>>>> either XXX is aborted or HHH does not terminate is insufficient >>>>> reason to call it an axiom. >>>>> >>>> >>>> *Premise* (assumed to be true) >>>> Any input that must be aborted to prevent >>>> the non termination of HHH >>>> >>>> *Logically entailed by the above premise* >>>> necessarily specifies non-halting behavior or >>>> it would never need to be aborted. >>> >>> No, it is not. Both "need to be" and "must be" are different from "is". >>> The correct asxiom is "If the program can be executed to its halting in >>> a finite time then the program specifies a halting behaviour." >>> >>>>>> From the fact that XXX must be aborted we can conclude that XXX >>>>>> must be aborted. >>>>> >>>>> Nothing that contains the word "must" is a fact. >>>>> >>>> >>>> When simulated input X stops running {if and only if} >>>> the simulation of this input X has been aborted this >>>> necessitates that input X specifies non-halting behavior. >>> >>> Nothing that contains the word "necessitates" is a fact, either. >>> Perhaps you should learn some philosophy. >>> >> >> >>      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. >> >> >> _DDD() >> [00002163] 55         push ebp      ; housekeeping >> [00002164] 8bec       mov ebp,esp   ; housekeeping >> [00002166] 6863210000 push 00002163 ; push DDD >> [0000216b] e853f4ffff call 000015c3 ; call HHH(DDD) >> [00002170] 83c404     add esp,+04 >> [00002173] 5d         pop ebp >> [00002174] c3         ret >> Size in bytes:(0018) [00002174] >> >> DDD emulated by HHH according to the semantic meaning of >> its x86 instructions never stops running unless aborted. > > That Professor Sipser does not express any agreement with anything > about the syntax of facts is not relevant to our (or any) discussion > about syntax of facts. > void DDD() { HHH(DDD); } int main() { DDD(); } 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. int main { DDD(); } calls HHH(DDD) that must abort the emulation of its input or HHH, emulated DDD and executed DDD never stop running. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer