Path: ...!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: The set of necessary FISONs Date: Wed, 29 Jan 2025 09:00:49 -0500 Organization: Peripheral Visions Lines: 18 Message-ID: References: <903de8e1-3538-4cfe-9f7a-6509eda47ab6@att.net> <3844edd7-0750-4418-bff6-2759817446b3@att.net> <27377646-137a-4f8f-a7bb-a75707b2da96@att.net> <965ee9868f28953d437113d0d38f069815499a3f@i2pn2.org> <77fb6230f3ef78f7524b70785c4772313e238258@i2pn2.org> <814297ada299a65bb9f427ddec5646afcc94be9f@i2pn2.org> <95ac176b19f1c24772a2ee73b3a12fe494da1241@i2pn2.org> <993b552f-7ab8-4a0b-a308-4748f20efb95@tha.de> Reply-To: erratic.howard@gmail.com MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15"; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 29 Jan 2025 15:00:54 +0100 (CET) Injection-Info: dont-email.me; posting-host="d98dd6ddbf7c6edbb0e20111cc565524"; logging-data="2539426"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+fa5DA2dlJWmep1gD+DxWPXD17sJB/2k4=" Cancel-Lock: sha1:YBccovzdy0DMmvPJ/Dy8Xn1Zk/Q= X-Newsreader: MesNews/1.08.06.00-gb X-ICQ: 1701145376 Bytes: 2544 WM was thinking very hard : > On 29.01.2025 10:36, FromTheRafters wrote: >> on 1/29/2025, WM supposed : >>> On 29.01.2025 05:07, Richard Damon wrote: >>> >>>> >>>> YOU are the one that says there needs to be a "required" FISON. >>> >>> If there is an infinite set, then it has a first element >> >> Still wrong. > > It is Cantor's theorem that every set of ordinals has a first element. FISONs > are v. Neumann ordinals. Yes, but some infinite sets don't have a first element. Perhaps you meant that if there is an infinite strictly monotonic increasing sequence of FISONs then there is a first FISON?