Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory Subject: Re: Halting Problem: What Constitutes Pathological Input Date: Mon, 5 May 2025 21:51:29 -0500 Organization: A noiseless patient Spider Lines: 57 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Tue, 06 May 2025 04:51:29 +0200 (CEST) Injection-Info: dont-email.me; posting-host="4d3877b25e07ae675aebb853b858fd37"; logging-data="2109150"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19JYji9FjxkcYADXUlJbPxe" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:SbbuYUR9dN8cfkRDUPfFdL+AZFk= X-Antivirus: Norton (VPS 250505-6, 5/5/2025), Outbound message In-Reply-To: Content-Language: en-US X-Antivirus-Status: Clean On 5/5/2025 9:27 PM, dbush wrote: > On 5/5/2025 10:18 PM, olcott wrote: >> On 5/5/2025 8:59 PM, dbush wrote: >>> On 5/5/2025 8:57 PM, olcott wrote: >>>> On 5/5/2025 7:49 PM, dbush wrote: >>>>> >>>>> Which starts with the assumption that an algorithm exists that >>>>> performs the following mapping: >>>>> >>>>> >>>>> 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 >>>>> >>>>> >>>>> >>>>>> DO COMPUTE THAT THE INPUT IS NON-HALTING >>>>>> IFF (if and only if) the mapping FROM INPUTS >>>>>> IS COMPUTED. >>>>> >>>>> i.e. it is found to map something other than the above function >>>>> which is a contradiction. >>>>> >>>> >>>> The above function VIOLATES COMPUTER SCIENCE. >>>> You make no attempt to show how my claim >>>> THAT IT VIOLATES COMPUTER SCIENCE IS INCORRECT >>>> you simply take that same quote from a computer >>>> science textbook as the infallible word-of-God. >>> >>> All you are doing is showing that you don't understand proof by >>> contradiction, >> >> Not at all. > > > Yes. > > The mapping is well defined. You don't even know that "well defined" means that all of the steps have been specified. In mathematics, a well-defined expression or unambiguous expression is an expression whose definition assigns it a unique interpretation or value. https://en.wikipedia.org/wiki/Well-defined_expression -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer