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: Functions computed by Turing Machines MUST apply finite string transformations to inputs --- MT Date: Sun, 4 May 2025 20:23:05 -0500 Organization: A noiseless patient Spider Lines: 54 Message-ID: References: <991dde3a60e1485815b789520c7149e7842d18f2@i2pn2.org> <-GOdnZvgEPn-84j1nZ2dnZfqn_SdnZ2d@brightview.co.uk> <2qydnbbWA6CAGIv1nZ2dnZfqn_SdnZ2d@brightview.co.uk> <87frhjamvt.fsf@bsb.me.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 05 May 2025 03:23:06 +0200 (CEST) Injection-Info: dont-email.me; posting-host="0a6320ec149f030cd98ca15e4d2d5e5f"; logging-data="3411565"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/DfS1COgMA6yFBItY5iw1J" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:5JN9dVxxujBX6jeioo85c9RP0eo= X-Antivirus-Status: Clean In-Reply-To: <87frhjamvt.fsf@bsb.me.uk> X-Antivirus: Norton (VPS 250504-4, 5/4/2025), Outbound message Content-Language: en-US Bytes: 4367 On 5/4/2025 8:04 PM, Ben Bacarisse wrote: > Mike Terry writes: > ... >> As explained above, UTM(⟨Ĥ⟩ ⟨Ĥ⟩) simulates Ĥ run with input Ĥ (having the >> same halting behaviour) and Ĥ run with input Ĥ HALTS. So embedded_H does >> not "gather enough information to deduce that UTM(⟨Ĥ⟩ ⟨Ĥ⟩) would never >> halt". THAT IS JUST A FANTASY THAT YOU HAVE. >> >> UTM(⟨Ĥ⟩ ⟨Ĥ⟩) DOES halt, so embedded_H can't possibly gather information >> that genuinely implies it DOESN'T halt. The explanation is obvious: >> embedded_H gathers information that *YOU* believe implies that UTM(⟨Ĥ⟩ ⟨Ĥ⟩) >> would never halt, but *YOU ARE SIMPLY WRONG*. > > He used to claim that false ("does not halt") was the correct answer, > /even though/ the computation in question halts! Those were simpler > days. Of course cranks will never admit to having been wrong about > anything other than a detail or two, so anyone who could be bothered > could try to get him to retract that old claim. > 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. When Ĥ is applied to ⟨Ĥ⟩ Ĥ.q0 ⟨Ĥ⟩ ⊢* embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qy ∞ Ĥ.q0 ⟨Ĥ⟩ ⊢* embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qn In other words embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩ is correct to reject its input if Ĥ.q0 ⟨Ĥ⟩ ⊢* UTM ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qy ∞ Ĥ.q0 ⟨Ĥ⟩ ⊢* UTM ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qn Would not halt. >> I know you'll not understand what I've just said, because it is all too >> abstract and you don't understand the concepts involved, and consequently >> you probably don't agree with my Sipser interpretation, and even if you did >> I doubt you would be able to work out its consequences. So I don't expect >> to be posting any further. > > Not you then! I sympathise, though my reason for not talking to him is > his unacceptable insults. > -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer