Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Ben Bacarisse Newsgroups: comp.theory Subject: Re: Every sufficiently competent C programmer knows Date: Thu, 13 Mar 2025 15:44:34 +0000 Organization: A noiseless patient Spider Lines: 83 Message-ID: <878qp9gckd.fsf@bsb.me.uk> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Injection-Date: Thu, 13 Mar 2025 16:44:36 +0100 (CET) Injection-Info: dont-email.me; posting-host="4d577e3c6150bb608d45a21a379c7fd7"; logging-data="3623792"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/JsqIi+nch720a4h+ZLCoxuxmWBCvGF3Q=" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:SpB7FTvIwrVJk5NDjIax2Ai7V74= sha1:rrhTlqz+2LtrSlRAF3Xroy/XW2M= X-BSB-Auth: 1.77cab6c21beb32badda3.20250313154434GMT.878qp9gckd.fsf@bsb.me.uk Bytes: 4623 Mike Terry writes: > On 11/03/2025 18:23, Richard Heathfield wrote: >> On 11/03/2025 17:42, Mike Terry wrote: >>> Finally, if you really want to see the actual HHH code, its in the >>> halt7.c file (along with DDD) that PO provides links to from time to >>> time.  However it's not very illuminating due to bugs/design >>> errors/misunderstandings which only serve to obfuscate PO's errors in >>> thinking. >> [I've now seen the code. Oh deary deary me.] > > :) > >> Thank you for a spirited attempt to be cogent - or at least as cogent as >> it is possible to be in the circumstances! >> I think PO's first step must be to demonstrate that HHH() correctly >> diagnoses some easy functions, such as these: > > Not really necessary - PO is not trying or claiming to have a (full) > halt decider. > > Originally his claim was that he had a program which worked for the > counter-example TM used in the common (e.g. Linz book) proof. That, of course, depends on the way the wind's blowing. For example in 2020: "The non-halting decider that I defined accepts any and all non-halting inputs and rejects any and all halting inputs." But then he retreated to the "once case" argument again until: Me: "Recent posts have said that you really do claim to have a halting decider. Have you extended your claim or was that a misunderstanding?" PO: "I really do have a halting decider." > ... Such a > program is impossible, as Linz and others prove, so having a program H and > its corresponding "counter-example" D, such that H correctly decides D, > would certainly show that the Linz proof is wrong. His claim was always > that he had "refuted the HP proof", or sometimes that he had refuted the HP > theorem itself although he's been told dozens of times that there are many > alternative proofs for the result. Way back in 2004 he was sure that: "I have correctly refuted each and every mechanism by which the [halting theorem] has been proven to be true. I have not shown that solving the Halting Problem is possible, merely refuted every proof that it is impossible." I expect a publication anytime. 20 years is just about enough to get all the details right. > [As it turned out, PO's D(D) halted when run under his x86utm environment, > while H(D,D) which is required to return the halting status of computation > D(D) returned 0 (=non-halting). That is exactly what the Linz proofs > claim!] We must always remember that PO has re-defined what it means for the answer to be correct: Me: "Here's the key question: do you still assert that H(P,P) == false is the "correct" answer even though P(P) halts?" PO: "Yes that is the correct answer even though P(P) halts." He's been quite clear about it: "When we make the single change that I suggest the halting problem ceases to be impossible to solve because this revised question is not subject to pathological self-reference." "This transforms an undecidable problem into a decidable problem." I hope you forgive me just chipping in with stuff you know perfectly well, but I thought I'd just give some background as Richard is a new participant and my comments fit better with your post than his. -- Ben.