Path: ...!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: Hypothetical possibilities Date: Mon, 22 Jul 2024 10:05:41 -0500 Organization: A noiseless patient Spider Lines: 71 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 22 Jul 2024 17:05:42 +0200 (CEST) Injection-Info: dont-email.me; posting-host="9aaf30c8a38b34dfe54399611020f1ec"; logging-data="719392"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/rsmuoOjGbSi4RIitCMxof" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:LO0rR3ZTEL37wUKELPr9d+11mrk= Content-Language: en-US In-Reply-To: Bytes: 3371 On 7/22/2024 6:05 AM, Mikko wrote: > On 2024-07-20 15:28:31 +0000, olcott said: > >> void DDD() >> { >>    HHH(DDD); >> } >> >> int main() >> { >>    DDD(); >> } >> >> (a) Termination Analyzers / Partial Halt Deciders must halt >> this is a design requirement. > > For a partial analyzer or deciders this is not always required. > *You can't even get my words correctly* A termination analyzer must report on the behavior of at least one input for all of the inputs of this one input. This is met when a termination analyzer analyzes an input having no inputs. A partial halt decider must correctly determine the halt status of at least one input and its specific input (if any). HHH is both a partial halt decider and a termination analyzer for DDD and a few other inputs having no input. >> (b) Every simulating termination analyzer HHH either >> aborts the simulation of its input or not. > > This must be interpreted to mean that a simulating termination analyzer > may abort its simulation for some simulated abort and simulate others > to the termination. > I am talking about hypothetical possible ways that HHH could be encoded. (a) HHH(DDD) is encoded to abort its simulation. (b) HHH(DDD) is encoded to never abort its simulation. >> (c) Within the hypothetical case where HHH does not abort >> the simulation of its input {HHH, emulated DDD and executed DDD} >> never stop running. > > The case is not very hypothetical. Given the HHH you already have, > it is fairly easy to construct the "hypothetical" HHH and see what > it actually does. > (a) HHH(DDD) is encoded to abort its simulation. (b) HHH(DDD) is encoded to never abort its simulation. >> This violates the design requirement of (a) therefore HHH must >> abort the simulation of its input. > > The violation simply means that the "hypothetical" HHH is not a > termination analyzer of partial halt decider in sense (a). What > it "must" be or do depends on the requirements. > Therefore (a) is correct and (b) is incorrect according to the design requirements for HHH that it must halt. It is also a truism that any input that must be aborted is a non-halting input. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer