Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: wij Newsgroups: comp.theory Subject: Re: Cantor Diagonal Proof Date: Sun, 06 Apr 2025 18:42:05 +0800 Organization: A noiseless patient Spider Lines: 58 Message-ID: <809a03d4b71e717fca7bf77bd900c4e977844c2d.camel@gmail.com> References: <7EKdnTIUz9UkpXL6nZ2dnZfqn_ednZ2d@brightview.co.uk> <45bb7521c3bb68fe5fd47d10ee93a03de17f8d47.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Injection-Date: Sun, 06 Apr 2025 12:42:07 +0200 (CEST) Injection-Info: dont-email.me; posting-host="ed44edb85b9ccc9a724188d6920c2cc1"; logging-data="843561"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/kTaTbRymfVLkgzSFxBW7Y" User-Agent: Evolution 3.54.3 (3.54.3-1.fc41) Cancel-Lock: sha1:AkMJdTtjp8A3g1R5SPzTBWCio+Q= In-Reply-To: Bytes: 3721 On Sun, 2025-04-06 at 13:35 +0300, Mikko wrote: > On 2025-04-06 07:15:51 +0000, wij said: >=20 > > On Sun, 2025-04-06 at 06:43 +0000, Lawrence D'Oliveiro wrote: > > > On Sun, 6 Apr 2025 07:27:43 +0100, Richard Heathfield wrote: > > >=20 > > > > On 06/04/2025 06:40, Lawrence D'Oliveiro wrote: > > > >=20 > > > > > On Sat, 5 Apr 2025 09:07:22 +0100, Richard Heathfield wrote: > > > > >=20 > > > > > > But to be computable, numbers must be computed in a finite numb= er of > > > > > > steps. > > > > >=20 > > > > > =E2=80=9CComputable Number: A number which can be computed to any= number of > > > > > digits desired by a Turing machine.=E2=80=9D > > > > >=20 > > > > > > > > >=20 > > > > "The =E2=80=9Ccomputable=E2=80=9D numbers may be described briefly = as the real numbers > > > > whose expressions as a decimal are calculable by finite means." - A= lan > > > > Turing. > > > >=20 > > > > And therefore, to be computable, numbers must be computed in a fini= te > > > > number of steps. > > >=20 > > > I would say you are quoting Turing out of context. By your>=20 > > > (mis)interpretation of his words, even something like 1/3 is an>=20 > > > incomputable number, since its =E2=80=9Cexpressions as a decimal are = not>=20 > > > calculable by finite means=E2=80=9D. > >=20 > > Simply put, repeating decimals are irrational. > > https://sourceforge.net/projects/cscall/files/MisFiles/RealNumber2-en.t= xt/download=C2=A0 > >=20 >=20 > Repeating decimals are rational. Prove it (be sure not to make mistakes shown in the link above) > An irrational number has an infinite > non-repeating sequence of digits. >=20 > > All your doubt should be addressed in the file of the link. > >=20 > > > Turing would not have been so dumb as to have his definition of>=20 > > > computability depend on something as trivial as the choice of number= =20 > > > base. >=20 >=20