Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: WM Newsgroups: sci.math Subject: Re: density of the reals Date: Wed, 11 Sep 2024 16:33:14 +0200 Organization: A noiseless patient Spider Lines: 21 Message-ID: References: <38ypmjbnu3EfnKYR4tSIu-WavbA@jntp> <34e11216-439f-4b11-bdff-1a252ac98f8f@att.net> <27b3b5e088d82d4475c68a64f50a4bccac9c6f29@i2pn2.org> <9eeba8a5041ce7ee48e5019d9e98d4ea38a1eb72@i2pn2.org> <89ed6d8de6c20d65e869d384181b642309f63bc4@i2pn2.org> <937a4a53c27b209538bb77bfe8059a90cc70ee9e@i2pn2.org> <0815cfde62cb548b23019eb4b4a8a3d3a1a15642@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 11 Sep 2024 16:33:13 +0200 (CEST) Injection-Info: dont-email.me; posting-host="1e93531ab4ad608edca54135e7debc51"; logging-data="3837128"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/xsYuybqSxBx23LyHIBO54fYufN6NA4aA=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:EDIqSh7V78f4CgbGrZ0jahsvbFk= Content-Language: en-US In-Reply-To: <0815cfde62cb548b23019eb4b4a8a3d3a1a15642@i2pn2.org> Bytes: 2709 On 11.09.2024 08:05, joes wrote: > Am Tue, 10 Sep 2024 21:13:57 +0200 schrieb WM: >> On 10.09.2024 20:38, Chris M. Thomasson wrote: >>> It seems that any non-zero gap can have unit fractions small enough to >>> fit in it... >> A gap of countably many points is not sufficient but is a subgap of >> every gap between unit fractions. > Why is it not sufficient? Because between any two unit fractions there are uncountably many points. > Since when are the reals countable? Every uncountable set has a countable subset, in fact uncountably many. The countable set (0, a) is a subinterval of the uncountable set (0, d) comprising ℵo unit fractions. No x of (0, a) can have smaller unit fractions. Well, perhaps one. Regards, WM >