Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: =?UTF-8?B?QW5kcsOpIEcuIElzYWFr?= Newsgroups: comp.theory Subject: Re: Turing Machine computable functions MUST apply finite string transformations to inputs Date: Thu, 1 May 2025 18:32:56 -0600 Organization: Christians and Atheists United Against Creeping Agnosticism Lines: 52 Message-ID: References: <87cyd5182l.fsf@nosuchdomain.example.com> <991dde3a60e1485815b789520c7149e7842d18f2@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 02 May 2025 02:32:57 +0200 (CEST) Injection-Info: dont-email.me; posting-host="353a54f44dbfd818bba0b562fc9f42ff"; logging-data="4034002"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19CzzzdQWYFCp9FaqElfgVs" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:UoZtblNswglzdqGqVMMYxqL1DfE= In-Reply-To: Content-Language: en-US Bytes: 3804 On 2025-05-01 14:15, olcott wrote: > On 5/1/2025 10:14 AM, André G. Isaak wrote: >> On 2025-04-30 21:50, olcott wrote: >>> On 4/30/2025 7:17 PM, André G. Isaak wrote: >> >>>> You are still hopelessly confused about your terminology. >>>> >>>> Computable functions are a subset of mathematical functions, and >>>> mathematical functions are *not* the same thing as C functions. >>>> Functions do not apply "transformations". They are simply mappings, >>>> and a functions which maps every pair of natural numbers to 5 is a >>>> perfectly legitimate, albeit not very interesting, function. >>>> >>>> What makes this function a *computable function* is that fact that >>>> it is possible to construct a C function (or a Turing Machine, or >>>> some other type of algorithm) such as int foo(int x, int y) {return >>>> 5;} which computes that particular function; but the C function and >>>> the computable function it computes are entirely separate entities. >>> >>> computes the sum of two integers >>> by transforming the inputs into an output. >>> int sum(int x, int y) { return x + y; } >>> >>> Computes no function because it ignores its inputs. >>> int sum(int x, int y) { return 5; } >> >> All you're demonstrating here is that you have no clue what a function >> is, nor, apparently, do you have any desire to learn. >> >> André >> > > What I am explaining is that a halt decider > must compute the mapping FROM THE INPUTS ONLY > by applying a specific set of finite string > transformations to the inputs. No. Halt deciders weren't even mentioned above. I was addressing your absurd claim that int foo(int x, int y) { return 5; } does not compute a function. This clearly indicates that you do not grasp the concept of "function". To understand what a halt decider does you need to first understand what the halting function is. And to understand that, you must first understand what a function is. You clearly do not. André -- To email remove 'invalid' & replace 'gm' with well known Google mail service.