Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Ben Bacarisse Newsgroups: sci.math Subject: Re: More complex numbers than reals? Date: Sun, 14 Jul 2024 02:30:50 +0100 Organization: A noiseless patient Spider Lines: 45 Message-ID: <87h6cskbed.fsf@bsb.me.uk> References: <87v81epj5v.fsf@bsb.me.uk> <878qyap1tg.fsf@bsb.me.uk> <871q40olca.fsf@bsb.me.uk> <87jzhsn4bn.fsf@bsb.me.uk> <0_MBIwFUmcbVzDRphAhSXT1Jfqk@jntp> <87sewejgk9.fsf@bsb.me.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Injection-Date: Sun, 14 Jul 2024 03:30:52 +0200 (CEST) Injection-Info: dont-email.me; posting-host="654b6c3918d78db6ef8aef8e07fa14fe"; logging-data="4033299"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19f02/FTaItAbDLZT9UkfKCW+z2IdGQibE=" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:CWswVz19McpwVU8j93FcM6BS0dI= sha1:tbP8hnbLFtoDvIpbxD9btyV+csQ= X-BSB-Auth: 1.79e4e28d4a27bae8bef8.20240714023050BST.87h6cskbed.fsf@bsb.me.uk Bytes: 2857 WM writes: > Le 13/07/2024 à 02:12, Ben Bacarisse a écrit : >> WM writes: >> (AKA Dr. Wolfgang Mückenheim or Mueckenheim who teaches "Geschichte des >> Unendlichen" > > and "Kleine Geschichte der Mathematik" Optional, I hope. >> at Hochschule Augsburg.) > > Meanwhile Technische Hochschule Augsburg. A sound name change that reflects the technical college's focus. >>> Le 11/07/2024 à 02:46, Ben Bacarisse a écrit : >>>> "Chris M. Thomasson" writes: >>> >>>>> {a, b, c} vs { 3, 4, 5 } >>>>> >>>>> Both have the same number of elements, >>>> That will fall down for infinite sets unless, by decree, you state that >>>> your meaning of "more" makes all infinite sets have the same number of >>>> elements. >>> >>> There are some rules for comparing sets which are not subset and superset, >>> namely symmetry: >> Still nothing about defining set membership, equality and difference in >> WMaths though. > > Are my rules appearing too reasonable for a believer in equinumerosity of > prime numbers and algebraic numbers? You can define equinumerosity any way you like. But you can't claim the "surprising" result of WMaths that E in P and P \ {E} = P whilst admitting that you have no workable definition of set membership, difference or equality. Presumably that's why you teach history courses now -- you can avoid having to write down even the most basic definitions of WMaths sets. -- Ben.