Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Richard Heathfield Newsgroups: comp.theory Subject: Re: Turing Machine computable functions apply finite string transformations to inputs +++ Date: Mon, 28 Apr 2025 21:21:32 +0100 Organization: Fix this later Lines: 33 Message-ID: References: <4818688e0354f32267e3a5f3c60846ae7956bed2@i2pn2.org> <65dddfad4c862e6593392eaf27876759b1ed0e69@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 28 Apr 2025 22:21:32 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5ec6b2a55f0a6c1e0abdb1bc19cf1947"; logging-data="82148"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18t6/HiUX9fw50bK61E9/B9hONmd46Ci3yeK/eX7GNcpQ==" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:vBxAhFXY/RBrZCSOsmH6eqc11pU= Content-Language: en-GB In-Reply-To: On 28/04/2025 21:03, olcott wrote: > On 4/28/2025 2:58 PM, dbush wrote: >> Category error.  The halting function below is fully defined, >> and this mapping is not computable *as you have explicitly >> admitted*. >> > > Neither is the square root of an actual onion computable. > > Turing Computable Functions are required to apply finite > string transformations to their inputs. The function defined > below ignores that requirement PROVING THAT IT IS INCORRECT. No, it proves that you agree that it's not a computable function. QED. >> Given any algorithm (i.e. a fixed immutable sequence of >> instructions) X described as with input Y: >> >> (,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 -- Richard Heathfield Email: rjh at cpax dot org dot uk "Usenet is a strange place" - dmr 29 July 1999 Sig line 4 vacant - apply within