Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Keith Thompson Newsgroups: comp.theory Subject: Re: Cantor Diagonal Proof Date: Mon, 07 Apr 2025 14:24:23 -0700 Organization: None to speak of Lines: 24 Message-ID: <875xjfd5rs.fsf@nosuchdomain.example.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Date: Mon, 07 Apr 2025 23:24:24 +0200 (CEST) Injection-Info: dont-email.me; posting-host="2714e7df686d80d73a1feebaa5e76a7a"; logging-data="687569"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18TLDttoGqH4ngVrapmNmY6" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:31dmk61u1X3/eiEDPQEXW8VAwGo= sha1:jWPObuopFC++qT47AF7n7kpkj1E= Bytes: 2462 Richard Heathfield writes: > On 07/04/2025 08:33, Lawrence D'Oliveiro wrote: [...] >> That’s not what “incomputable” means. > > Yeah, it is. We've already had this argument. Turing won: "The > "computable" numbers may be described briefly as the real numbers > whose expressions as a decimal are calculable by finite means." [...] That's a little too briefly. Quoting Wikipedia: In mathematics, computable numbers are the real numbers that can be computed to within any desired precision by a finite, terminating algorithm. By dropping the "to within any desired precision", your description implies (unintentionally, I'm sure) that pi is not computable. -- Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com void Void(void) { Void(); } /* The recursive call of the void */