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 --- Truthmaker Maximalism Date: Fri, 14 Mar 2025 20:27:42 -0500 Organization: A noiseless patient Spider Lines: 113 Message-ID: References: <5429f6c8b8a8a79e06b4aeefe677cc54a2a636bf@i2pn2.org> <924e22fc46d629b311b16a954dd0bed980a0a094@i2pn2.org> <0c100c3673494d00bdc02acd44b2d5b930bd2212.camel@gmail.com> <6c64432865001be54d691f8ef0cc89ddc71d18b6.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sat, 15 Mar 2025 02:27:43 +0100 (CET) Injection-Info: dont-email.me; posting-host="089deb6da5a8e3479213476df9745f18"; logging-data="2537802"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+bEFrwTlcFAoZ/S+vqrYyu" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:REYINmFYqfAE0hx5PSg8bzEsbMY= X-Antivirus: Norton (VPS 250314-6, 3/14/2025), Outbound message X-Antivirus-Status: Clean In-Reply-To: Content-Language: en-US Bytes: 6022 On 3/14/2025 8:00 PM, dbush wrote: > On 3/14/2025 8:45 PM, olcott wrote: >> On 3/14/2025 12:54 PM, dbush wrote: >>> On 3/14/2025 12:33 PM, olcott wrote: >>>> On 3/14/2025 11:01 AM, wij wrote: >>>>> On Fri, 2025-03-14 at 10:51 -0500, olcott wrote: >>>>>> On 3/14/2025 10:04 AM, wij wrote: >>>>>>> On Fri, 2025-03-14 at 09:35 -0500, olcott wrote:>> >>>>>>>> void DDD() >>>>>>>> { >>>>>>>>      HHH(DDD); >>>>>>>>      return; >>>>>>>> } >>>>>>>> >>>>>>>> DDD correctly simulated by HHH cannot possibly reach >>>>>>>> its own "return" instruction in any finite number of >>>>>>>> correctly simulated steps. >>>>>>>> >>>>>>>> That you are clueless about the semantics of something >>>>>>>> as simple as a tiny C function proves that you are not >>>>>>>> competent to review my work. >>>>>>>> >>>>>>> >>>>>>> https://en.wikipedia.org/wiki/Halting_problem >>>>>>> In computability theory, the halting problem is the problem of >>>>>>> determining, from a description of >>>>>>> an >>>>>>> arbitrary computer program and an input, whether the program will >>>>>>> finish running, or continue to >>>>>>> run >>>>>>> forever. >>>>>>> >>>>>>> That means: H(D)=1 if D() halts and H(D)=0 if D() does not halt. >>>>>>> >>>>>>> But, it seems you don't understand English, as least as my >>>>>>> level, .... >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> void DDD() >>>>>> { >>>>>>     HHH(DDD); >>>>>>     return; >>>>>> } >>>>>> >>>>>> The only difference between HHH and HHH1 is that they are >>>>>> at different locations in memory. DDD simulated by HHH1 >>>>>> has identical behavior to DDD() directly executed in main(). >>>>>> >>>>>> The semantics of the finite string input DDD to HHH specifies >>>>>> that it will continue to call HHH(DDD) in recursive simulation. >>>>>> >>>>>> The semantics of the finite string input DDD to HHH1 specifies >>>>>> to simulate to DDD exactly once. >>>>>> >>>>>> When HHH(DDD) reports on the behavior that its input finite >>>>>> string specifies it can only correctly report non-halting. >>>>>> >>>>>> When HHH(DDD) is required to report on behavior other than >>>>>> the behavior that its finite string specifies HHH is not >>>>>> a decider thus not a halt decider. >>>>>> >>>>>> All deciders are required to compute the mapping from >>>>>> their input finite string to the semantic or syntactic property >>>>>> that this string specifies. Deciders return true when this >>>>>> string specifies this property otherwise they return false. >>>>>> >>>>> >>>>> Are you solving The Halting Problem or not? Yes or No. >>>>> >>>>> >>>> >>>> I have only correctly refuted the conventional halting >>>> problem proof. >>> >>> And what exactly do you think this proof is proving?  More >>> specifically, what do you think the Linz proof is proving? >> >> All of the proofs merely show that there cannot >> possibly exist any halt decider that returns a >> value corresponding to the behavior of any input >> that is actually able to do the opposite of whatever >> value is returned. >> > Not exactly.  What they prove is that no H exists that satisfies these > requirements: > > > Given any algorithm (i.e. a fixed immutable sequence of instructions) X > described as with input Y: > > A solution to the halting problem is an algorithm H that computes the > following mapping: > > (,Y) maps to 1 if and only if X(Y) halts when executed directly > (,Y) maps to 0 if and only if X(Y) does not halt when executed directly > The executed directly part is bogus as I have shown and your indoctrination blindly ignores. The easiest way to see that it is wrong that is not over the head of everyone here (the behavior semantics that a finite string specifies) is that the above definition allows self-contradiction to derive undecidability. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer