Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: "Chris M. Thomasson" Newsgroups: sci.math Subject: Re: Incompleteness of Cantor's enumeration of the rational numbers (extra-ordinary) Date: Mon, 2 Dec 2024 22:07:09 -0800 Organization: A noiseless patient Spider Lines: 71 Message-ID: References: <23311c1a-1487-4ee4-a822-cd965bd024a0@att.net> <71758f338eb239b7419418f49dfd8177c59d778b@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 03 Dec 2024 07:07:09 +0100 (CET) Injection-Info: dont-email.me; posting-host="f777e730b2e8168ebcdb2932c05660c1"; logging-data="4083310"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19qP0R3laNoxOaZAapATMmbon+8R04IUHY=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:4+rDnrVps4rQ9wWI06+VuYTjX50= In-Reply-To: Content-Language: en-US Bytes: 3670 On 12/2/2024 10:01 PM, Chris M. Thomasson wrote: > On 12/2/2024 9:47 PM, Moebius wrote: >> Am 03.12.2024 um 06:34 schrieb Chris M. Thomasson: >> >>> What about {1, 2, 3, ..., n}, where n is taken to infinity? No limit? >> >> It's slightly complicated. :-P >> >> If we explicitly refer to sets, say, the sets S_1, S_2, S_3, ... >> >> We may call the sequence (S_1, S_2, S_3, ...) a "set sequence". >> >> Moreover we may define a certain limit (for such sequences) called >> "set limit". >> >> Then the following can be shown: >> >>       lim_(n->oo) {1, 2, 3, ..., n} = {1, 2, 3, ...} . >> >> Or, using defined symbols: >> >>       lim_(n->oo) F(n) = IN . >> >> [ The sequence here is (F(1), F(2), F(3), ...). It's limit IN. ] >> >> On the other hand: >> >>       lim_(n->oo) {n, n+1, n+2, ...} = {} . >> >> Hope this helps. :-P >> >> . >> . >> . >> > > Sometimes I like to think of the set of all natural numbers as an n-ary > tree, binary here, wrt zero as a main root, so to speak: > >             0 >            / \ >           /   \ >          /     \ >         /       \ >        1         2 >       / \       / \ >      /   \     /   \ >     3     4   5     6 >  ......................... > > On and on. A lot of math can be applied to it. wrt 2-ary: Roots of 5 and 6: (5-1)/2 = 2 (6-2)/2 = 2 Roots of 3 and 4: (3-1)/2 = 1 (4-2)/2 = 1 Roots of 1 and 2: (1-1)/2 = 0 (2-2)/2 = 0 Roots of 7 and 8: (7-1)/2 = 3 (8-2)/2 = 3 ?