Path: ...!news.nobody.at!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: immibis Newsgroups: comp.theory,sci.logic Subject: Re: D correctly simulated by H cannot possibly halt --- templates and infinite sets Date: Thu, 30 May 2024 12:11:24 +0200 Organization: A noiseless patient Spider Lines: 43 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Thu, 30 May 2024 12:11:24 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5c404f25cf9b215421e2879ba98f773a"; logging-data="1734475"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/0ZAaDBMatUylBGTN8bGLk" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:+8raXAKjz1gHWyMP2N16lYNpk/c= In-Reply-To: Content-Language: en-US Bytes: 3057 On 30/05/24 05:48, olcott wrote: > On 5/29/2024 9:55 PM, Richard Damon wrote: >> On 5/29/24 10:36 PM, olcott wrote: >>> On 5/29/2024 9:25 PM, Richard Damon wrote: >>>> On 5/29/24 9:55 PM, olcott wrote: >>>>> When the category is examined all at once then there is no need >>>>> to look at each individual element. >>>> >>>> So, which one or ones gave the correct answer for their input? >>>> >>> >>> *Formalizing the Linz Proof structure* >>> ∃H  ∈ Turing_Machines >>> ∀x  ∈ *Turing_Machines_Descriptions* >>> ∀y  ∈ Finite_Strings >>> such that H(x,y) = Halts(x,y) >>> >>> When we formalize it that way then some simulating halt deciders >>> get the correct answer. >>> >>> *Everyone else implicitly assumes this incorrect formalization* >>> ∃H  ∈ Turing_Machines >>> ∀x  ∈ *Turing_Machines* >>> ∀y  ∈ Finite_Strings >>> such that H(x,y) = Halts(x,y) >>> >>> >> >> Nope. >> >> You just don't understand the meaning of a "Description" in the problem. >> > > A deciders compute the mapping FROM ITS INPUTS > to it own accept or reject state > Deciders cannot take ACTUAL TURING MACHINES AS INPUTS > Deciders can only take FINITE STRINGS AS INPUTS > If you want to be pedantic, you made the mistake. It's actually H(DescriptionOf(x),y) = Halts(x,y) DescriptionOf is an injective function that converts Turing machines into finite strings.