Path: ...!weretis.net!feeder9.news.weretis.net!news.quux.org!eternal-september.org!feeder2.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: FromTheRafters Newsgroups: sci.math Subject: Re: Incompleteness of Cantor's enumeration of the rational numbers Date: Tue, 19 Nov 2024 11:42:12 -0500 Organization: Peripheral Visions Lines: 56 Message-ID: References: <157a949d-6c19-4693-8cee-9e067268ae45@att.net> <8165b44b-1ba5-429d-8317-0b043b214b53@att.net> 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: Tue, 19 Nov 2024 17:42:15 +0100 (CET) Injection-Info: dont-email.me; posting-host="c65860b81c1be1d790afb6c2f66366c7"; logging-data="2037000"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18s0agvvpTWN59pE/I/dfgihsFgkTOu0TM=" Cancel-Lock: sha1:UAlTXbM8xuhUcb/nhe4wSg925YE= X-ICQ: 1701145376 X-Newsreader: MesNews/1.08.06.00-gb Bytes: 3824 WM submitted this idea : > On 18.11.2024 23:40, FromTheRafters wrote: >> WM wrote on 11/18/2024 : >>> On 18.11.2024 22:58, FromTheRafters wrote: >>>> on 11/18/2024, WM supposed : >>>>> On 18.11.2024 18:15, FromTheRafters wrote: >>>>>> WM brought next idea : >>>>> >>>>>>>> >ℕ| - |ℕ| = 0 because if you subtract one element from ℕ then you >>>>>>>> have >>>>>>> no longer ℕ and therefore no longer |ℕ| describing it. >>>>>> >>>>>> Still wrong. >>>>> >>>>> If you remove one element from ℕ, then you have still ℵo but no longer >>>>> all elements of ℕ. >>>> >>>> But you do have now a proper subset of the naturals the same size as >>>> before. >>> >>> It has one element less, hence the "size" ℵo is a very unsharp measure. >> >> Comparing the size of sets by bijection. Bijection of finite sets give you >> a same number of elements, bijection of infinite sets give you same size of >> set. > > Why? Because only potential infinity is involved. True bijections pr5ove > equinumerosity. >>>>> If |ℕ| describes the number of elements, then it has changed to |ℕ| - 1. >>>> >>>> Minus one is not defined. >>> >>> Subtracting an element is defined. |ℕ| - 1 is defined as the number of >>> elements minus 1. >> >> Nope! > > The number of ℕ \ {1} is 1 less than ℕ. >> >>>>> If you don't like |ℕ| then call this number the number of natural >>>>> numbers. >>>> >>>> Why would I do that when it is the *SIZE* of the smallest infinite set. >>> >>> The set of prime numbers is smaller. >> >> No, it is not. > > It is, because 4 and 8 are missing. > > > There is a bijection. > > Only between numbers which have more successors than predecessors, although > it is claimed that no successors are remaining. You are not making any sense.