Path: news.eternal-september.org!eternal-september.org!feeder3.eternal-september.org!i2pn.org!i2pn2.org!.POSTED!not-for-mail From: Richard Damon Newsgroups: sci.math Subject: Re: Incompleteness of Cantor's enumeration of the rational numbers (extra-ordinary) Date: Wed, 8 Jan 2025 20:26:52 -0500 Organization: i2pn2 (i2pn.org) Message-ID: References: <98519289-0542-40ce-886e-b50b401ef8cf@att.net> <8e95dfce-05e7-4d31-b8f0-43bede36dc9b@att.net> <53d93728-3442-4198-be92-5c9abe8a0a72@att.net> <9c18a839-9ab4-4778-84f2-481c77444254@att.net> <8ef20494f573dc131234363177017bf9d6b647ee@i2pn2.org> <66868399-5c4b-4816-9a0c-369aaa824553@att.net> <417ff6da-86ee-4b3a-b07a-9c6a8eb31368@att.net> <07258ab9-eee1-4aae-902a-ba39247d5942@att.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Thu, 9 Jan 2025 01:26:52 -0000 (UTC) Injection-Info: i2pn2.org; logging-data="2696063"; mail-complaints-to="usenet@i2pn2.org"; posting-account="diqKR1lalukngNWEqoq9/uFtbkm5U+w3w6FQ0yesrXg"; User-Agent: Mozilla Thunderbird X-Spam-Checker-Version: SpamAssassin 4.0.0 Content-Language: en-US In-Reply-To: On 1/8/25 5:06 PM, WM wrote: > On 08.01.2025 20:19, Jim Burns wrote: >> On 1/8/2025 4:16 AM, WM wrote: >>> On 08.01.2025 00:50, Jim Burns wrote: >> >>>> The cardinal:ordinal distinction >>>> -- which does not matter in the finite domain >>>> matters in the infinite domain. >>> >>> The reason is that >>> the infinite cardinal ℵ₀ is based on >>> the mapping of the potentially infinite collection of >>> natural numbers n, >>> all of which have >>> infinitely many successors. >>> The cardinal ℵ₀ is not based on >>> the mapping of >>> the actually infinite set ℕ where >>> ℕ \ {1, 2, 3, ...} = { }. >> >> For each set smaller.than a fuller.by.one set, >> the cardinal:ordinal distinction doesn't matter. >> Cardinals and ordinals always go together. >> >> For each set smaller.than a fuller.by.one set >> there is an ordinal of its size in >> the set ℕ of all finite ordinals. >> >> Each set for which >> there is NOT an ordinal of its size in >> the set ℕ of all finite ordinals >> is NOT a set smaller.than a fuller.by.one set. > > The set {1, 2, 3, ...} is smaller by one element than the set {0, 1, 2, > 3, ...}. Proof: {0, 1, 2, 3, ...} \ {1, 2, 3, ...} = {0}. Cardinality > cannot describe this difference because it covers only mappings of > elements which have almost all elements as successors. > > Regards, WM > But Alelph_0, the size of the second, is also the size of the first, as Aleph_0 - 1 is Aleph_0. The fact that your brain can't handle that fact of infinite numbers is YOUR problem, not a problem with mathematics.