Path: ...!weretis.net!feeder9.news.weretis.net!news.quux.org!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: FromTheRafters Newsgroups: sci.math Subject: Re: Incompleteness of Cantor's enumeration of the rational numbers (extra-ordinary) Date: Sun, 19 Jan 2025 08:29:30 -0500 Organization: Peripheral Visions Lines: 42 Message-ID: References: <494bfd3b-3c70-4d8d-9c70-ce917c15fc22@att.net> <72142d82-0d71-460a-a1be-cadadf78c048@att.net> <812e64b1-c85c-48ac-a58c-e8955bc02f8c@att.net> <22b74adc-bf38-4aa4-a44f-622f0a2a5c41@att.net> <77a1069f5c5b8f95927ed9a33ecc6374c9d0a2dd@i2pn2.org> <20e517f6-d709-46fd-83f8-04c6b4fe9f59@tha.de> <4679319ea238a03fb042ae0c4de078c1a310c8a5@i2pn2.org> <320edbb95673eb535f81c16a471811fef7d0f752@i2pn2.org> Reply-To: erratic.howard@gmail.com MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 19 Jan 2025 14:29:32 +0100 (CET) Injection-Info: dont-email.me; posting-host="e5555fdd772255afcd74904ebfc57623"; logging-data="2372235"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/hR5daZOvfZ5qslve+x2WrfEUUz2PAUIE=" Cancel-Lock: sha1:vNKYgmrd+HV3UpLF72GMAmSWiBc= X-Newsreader: MesNews/1.08.06.00-gb X-ICQ: 1701145376 Bytes: 3399 WM formulated the question : > On 19.01.2025 11:42, FromTheRafters wrote: >> WM presented the following explanation : >>> On 18.01.2025 12:03, joes wrote: >>>> Am Fri, 17 Jan 2025 22:56:13 +0100 schrieb WM: >>> >>>>> Correct. If infinity is potential. set theory is wrong. >>>> And that is why set theory doesn't talk about "potential infinity". >>> >>> Nevertheless it uses potential infinity. >> >> No, it doesn't. > > Use all natnumbers individually such that none remains. Fail. This makes no sense. >>> All "bijections" yield the same cardinality because only the potentially >>> infinite parts of the sets are  applied. >> >> No, it is because these bijections show that some infinite sets' sizes can >> be shown to be equal even if no completed count exists. > > They appear equal because no completed count exists. No, they are the same size when it is shown there is at least one bijection. Still, no counting necessary. > All natnumbers in bijections have ℵ₀ not applied successors. > ∀n ∈ ℕ_def: |ℕ \ {1, 2, 3, ..., n}| = ℵo > Only potential infinity is applied. You mean that only finite sets are involved. > In actual infinity all natnumbers would be applied: > ℕ \ {1, 2, 3, ...} = { } That is simply 'infinity' which means not finite. > But that is not possible in bijections. Sure it is, when they are infinite.