Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site watmath.UUCP Path: utzoo!watmath!csc From: csc@watmath.UUCP (Computer Sci Club) Newsgroups: net.math Subject: Re: Interesting number proof invalid Message-ID: <7727@watmath.UUCP> Date: Fri, 11-May-84 13:43:39 EDT Article-I.D.: watmath.7727 Posted: Fri May 11 13:43:39 1984 Date-Received: Sat, 12-May-84 10:21:55 EDT References: <7672@watmath.UUCP> <2457@allegra.UUCP>, <130@westcsr.UUCP> Organization: U of Waterloo, Ontario Lines: 20 ... The proof that all numbers are interesting (given the questionable assumption that the least uninteresting number is interesting) is not an inductive proof but a proof by contradiction. If we assume the set of non-interesting numbers is non empty then there is a least non- interesting number which is by assumption an element of both sets (we do not remove it from the set of non-interesting numbers, it is already assumed to be an element of that set) and we have a contradiction. This proof is quite valid and very silly. Note also, although under the normal ordering of the reals, there exist subsets with no least element, there exists (if like all right thinking mathematicians you accept the axiom of choice) an ordering of the reals such that every subset has a least element. Hence it follows that all real numbers are interesting! William Hughes DOWN WITH INTUITIONISM!!