I've mostly missed the train on this, but if I could quickly bring up a couple of comments from earlier in the thread(s). Paraphrasing: 1. infinity is not a number 2. something about 1/inf and infinity stuff being INEXACT my responses: 2. 1/inf = 0 *IS* exact. It is inexact while approaching inf, but finally exactly 0 'at' infinity. 1. depends on your definition of 'number'. You can definitely say infinity is not an integer. (NaI ?) But for a reasonable definition of 'number' infinity IS a number (or more accurately, a bunch of numbers, as there is a bunch of infinities). The best definition, that I know of for number is "The answer to the question: 'how many?' " and infinity fulfills that definition. And now some background, and why I bring this up - Many moons ago when the web was young-ish, I took Gottlob Frege as a 'web-identity' (back when alta-vista was a search engine and Yahoo was king and wanted all your personal info, etc...), and as a habit I have carried it around ever since. Call me Gottlob on the web vs Tony (my real name) and I usually don't even notice. Anyhow, the real Gottlob Frege was a turn of the century Mathematician/Philosopher. He wrote an excellent book called "The Foundations of Arithmetic" - one of my favorites. It mainly attempted to answer the question "what is a number". The first answer is that it is the answer to the question 'how many' (for mathematicians this is now called 'cardinality'). After that answer the book moves forward and gets quite interesting and complicated. Anyhow, whenever anyone says infinity is not a number, I feel compelled to reply that it answers the question 'how many", and thus is a number. ( Typically the more precise question is 'how many integers are there" and the answer being aleph0 or 'aleph-not' - the first infinity). Anyhow, feel free to ignore this. I'm not actually taking sides on whether/how you treat NaN/infinity - sounds like you may be able to avoid it altogether. P.S. for the logicians out there - he was also basically the first to introduce rules for quantifiers "For all", "there exists at least one", etc; And for all those wearing programmer-hats instead of their mathematician-hats: I also consider Gottlob Frege the father of 'duck-typing'. A man before his time... Tony