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: Every sufficiently competent C programmer knows --- Paraphrase of Sipser's agreement Date: Sun, 16 Mar 2025 10:05:40 -0500 Organization: A noiseless patient Spider Lines: 88 Message-ID: References: <1571d378add9779a0986b4df903964c7241f94a7@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 16 Mar 2025 16:05:41 +0100 (CET) Injection-Info: dont-email.me; posting-host="07a083537033e8637263f61b76c22e15"; logging-data="2045751"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+JqFZ2JRqRVxQXSFx+u4gk" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:0ZOXns2srZ93UJ+4K7eH7SYOe7E= X-Antivirus: Norton (VPS 250316-2, 3/16/2025), Outbound message X-Antivirus-Status: Clean Content-Language: en-US In-Reply-To: <1571d378add9779a0986b4df903964c7241f94a7@i2pn2.org> Bytes: 5002 On 3/16/2025 7:31 AM, joes wrote: > Am Sat, 15 Mar 2025 16:27:00 -0500 schrieb olcott: >> On 3/15/2025 5:12 AM, Mikko wrote: >>> On 2025-03-14 14:39:30 +0000, olcott said: >>>> On 3/14/2025 4:03 AM, Mikko wrote: >>>>> On 2025-03-13 20:56:22 +0000, olcott said: >>>>>> On 3/13/2025 4:22 AM, Mikko wrote: >>>>>>> On 2025-03-13 00:36:04 +0000, olcott said: >>>>>>> >>>>>>> >>>>>>>> void DDD() >>>>>>>> { >>>>>>>>    HHH(DDD); >>>>>>>>    return; >>>>>>>> } >>>>>>>> int DD() >>>>>>>> { >>>>>>>>    int Halt_Status = HHH(DD); >>>>>>>>    if (Halt_Status) >>>>>>>>      HERE: goto HERE; >>>>>>>>    return Halt_Status; >>>>>>>> } >>>>>>>> >>>>>>>> When HHH correctly emulates N steps of the above functions none of >>>>>>>> them can possibly reach their own "return" instruction and >>>>>>>> terminate normally. >>>>>>> >>>>>>> Nevertheless, assuming HHH is a decider, Infinite_Loop and >>>>>>> Infinite_Recursion specify a non-terminating behaviour, DDD >>>>>>> specifies a terminating behaviour >>>>>> >>>>>> What is the sequence of machine language instructions of DDD >>>>>> emulated by HHH such that DDD reaches its machine address 00002183? >>>>> >>>>> Irrelevant off-topic distraction. >>>> >>>> Proving that you don't have a clue that Rice's Theorem is anchored in >>>> the behavior that its finite string input specifies. >>> >>> Another irrelevant off-topic distraction, this time involving a false >>> claim. >>> One can be a competent C programmer without knowing anyting about >>> Rice's Theorem. >> YES. >> >>> Rice's Theorem is about semantic properties in general, not just >>> behaviours. >>> The unsolvability of the halting problem is just a special case. >>> >> Does THE INPUT TO simulating termination analyzer HHH encode a C >> function that reaches its "return" >> instruction [WHEN SIMULATED BY HHH] (The definition of simulating >> termination analyzer) ??? > That can't be right. Otherwise my simulator could just not simulate > at all and say that no input halts. > Originally a "decider" was any TM that always stops running for any reason. In computability theory, a decider is a Turing machine that halts for every input.[1] https://en.wikipedia.org/wiki/Decider_(Turing_machine) >> >> > key word "correctly" > *I anchored what correct emulation means now* If emulating termination analyzer H emulates its input finite string D of x86 machine language instructions according to the semantics of the x86 programming language until H correctly determines that this emulated D cannot possibly reach its own "ret" instruction in any finite number of correctly emulated steps then H can abort its emulation of input D and correctly report that D specifies a non-halting sequence of configurations. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer