Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site harvard.ARPA Path: utzoo!linus!philabs!cmcl2!seismo!harvard!macrakis From: macrakis@harvard.ARPA (Stavros Macrakis) Newsgroups: net.math Subject: (0,1) -> [0,1] bijection Message-ID: <140@harvard.ARPA> Date: Thu, 23-May-85 14:21:20 EDT Article-I.D.: harvard.140 Posted: Thu May 23 14:21:20 1985 Date-Received: Sat, 25-May-85 05:33:32 EDT References: <7368@ucbvax.ARPA> <376@h-sc1.UUCP> Reply-To: macrakis@harvard.UUCP (Stavros macrakis) Organization: Aiken Comp. Lab., Harvard Lines: 10 Keywords: mapping Problem: map (0,1) to [0,1] bijectively. Insight: it's easy to map any countable set bijectively into any of its infinite subsets. Solution: choose some ordering of ANY countable subset of (0,1). Map the first and second elements to 0 and 1. Map the nth element to the n-2nd element. Leave everything else alone. The earlier posted solution is a special case of this.