The original unum proposal is in [1] which was very interesting read. This is a newer version of the format that replaces NaN with a notion of an empty set and represents 1/x exactly. Rather splendid!<p>[1] <a href="http://www.amazon.com/The-End-Error-Computing-Computational/dp/1482239868" rel="nofollow">http://www.amazon.com/The-End-Error-Computing-Computational/...</a>