From: Paul Lutus Date: 2006-09-02T10:10:26+09:00 Subject: Re: Happy Numbers (#93) Matthew Moss wrote: >> Out of interest, any mathmaticians care to enlighten me as to whether >> happy numbers are in any way "useful"? > > As has been said, "real mathematicians" shudder that their work might be > useful. > > In actuality, sometimes things like this aren't, and sometimes they > are years later. Prime numbers never had much use until recent years, > where they have become very important for encryption. Another example is non-Euclidean geometry, which was an impractical, exotic plaything for about 100 years, until general relativity came along and required it. Without non-Euclidean geometry, Einstein wouldn't have been able to express GR at all. Prior to that, few would have guessed that the universe isn't Euclidean. -- Paul Lutus http://www.arachnoid.com