More geeking. John has between 2 and 5 apples. Mary gives him between 3 and 7 apples. How many apples does he have now? If you can understand this simple question, you have the gist interval arithmetic.

I first heard of interval arithmetic while working at Kennedy Space Center; we used it to model pressures and temperatures of liquid oxygen flowing through pipes. There are other applications beyond physical modeling. It is sometimes used in finance to track the rounding error during financial calculation, so people can't steal fractions of cent from each transaction (like they did in Office Space).

I've started a project that provides a Java library for developers wishing to use interval arithmetic for whatever purpose they want: check it out. It's open-source, so anyone is free to download, use, and even modify it. It's still in a very raw state, but I'm hoping to improve it, especially if there is outside interest.

(I'm torn about hosting it on SourceForge; they're the biggest and most widely known repository for projects such as these, but I hate hate hate Unix-y interfaces, huge lists of features that nobody uses, and sparse and inconsistent documentation, and that's what SourceForge seems to be all about. Maybe I'll switch to Google's?)