Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Moebius Newsgroups: sci.math Subject: Re: How many different unit fractions are lessorequal than all unit fractions? Date: Mon, 23 Sep 2024 01:44:19 +0200 Organization: A noiseless patient Spider Lines: 24 Message-ID: References: <4faa63d0ff8c163f01a38736aeb5732184218a29@i2pn2.org> <87414b50e6265e6e443c4486913201749f2696ed@i2pn2.org> <5b130929c7f56ea83246b7f6534ba5fae4598c62@i2pn2.org> <2551da6710975930f68b61f8e76ea6990411168b@i2pn2.org> <2c1940845e336c71cf55b737945d3132b1a41e62@i2pn2.org> <59204af99930441bf5a2cb92d80a34e25a0d0835@i2pn2.org> <649d66170b7274e49882940c18cde7817e62c560@i2pn2.org> Reply-To: invalid@example.invalid MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Mon, 23 Sep 2024 01:44:20 +0200 (CEST) Injection-Info: dont-email.me; posting-host="773aae99b42f03f72b981c35c4a186a2"; logging-data="2524863"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/IIxK3tBAbXYyRZoF4pIGS" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:MKHvmnRhcC2OC86mFXcVFnIVClA= Content-Language: de-DE In-Reply-To: Bytes: 2731 Am 23.09.2024 um 01:35 schrieb Moebius: > Am 23.09.2024 um 01:28 schrieb Chris M. Thomasson: > > Concerning the integers: > >> [...} each number has infiniteLY MANY predecessors and infiniteLY MANY >> successors. > > ... Btw. we might define "signed unit fractions" too (just for fun). Def.: x e IR is a /signed unit fraction/ iff there is an z in Z such that x = 1/z. Then the signed unit fractions are just the numbers -1/1, -1/2, -1/3, ... ... 1/3, 1/2, 1/1. 0 would be a very special point here. No signed unit fraction, but "surrounded" by infinitely many signed unit fractions. Moreover, they would be arbitrarilly dense "there" (i.e. in the environment of 0).