Path: ...!2.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: WM Newsgroups: sci.math Subject: Re: How many different unit fractions are lessorequal than all unit fractions? (infinitary) Date: Thu, 10 Oct 2024 20:18:48 +0200 Organization: A noiseless patient Spider Lines: 37 Message-ID: References: <4bc3b086-247a-4547-89cc-1d47f502659d@tha.de> <17f710716a0a8a6049a231aacb27f90f14dc756d@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Thu, 10 Oct 2024 20:18:48 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5a3097e3986a32338a92b2aee4985ff2"; logging-data="3420388"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18PYaG48MdcK9v44FQUOAWPlUG3lbxbSgs=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:9Zabqs1mdivcEYyTqotUDe5AsYk= Content-Language: en-US In-Reply-To: <17f710716a0a8a6049a231aacb27f90f14dc756d@i2pn2.org> Bytes: 3077 On 09.10.2024 19:47, joes wrote: > Am Wed, 09 Oct 2024 18:56:29 +0200 schrieb WM: >> Am 09.10.2024 um 18:12 schrieb Alan Mackenzie: >>> WM wrote: >> > Especially since both all segments are infinite, > and there are infinitely many of them. Impossible. Infinite endsegments contain almost all numbers. Therefore it is not possible that almost all numbers are used as indices. > >>>>>>>> Note: The shrinking endsegments cannot acquire new numbers. >>>>>>> An end segment is what it is. It doesn't change. >>>>>> But the terms of the sequence do. Here is a simple finite example: >>>>>> {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} >>>>>> {2, 3, 4, 5, 6, 7, 8, 9, 10} >>>>>> {3, 4, 5, 6, 7, 8, 9, 10} >>>>>> {4, 5, 6, 7, 8, 9, 10} >>>>>> {5, 6, 7, 8, 9, 10} >>>>>> {6, 7, 8, 9, 10} >>>>>> {7, 8, 9, 10} >>>>>> {8, 9, 10} >>>>>> {9, 10} >>>>>> {10} >>>>>> { } . >> The completion of the above sets does not change the principle: >> Non-empty inclusion-monotonic sets like infinite endsegments have a >> non-empty intersection. All endsegments have an empty intersection. > You should really be more careful with your phrasing. Intersection with > what? The intersection of all endsegments containing at least 3 numbers with just these endsegments contains 3 numbers. The intersection of all endsegments with all endsegments is empty. Regards, WM