Thanks for making the difference with more conventional ideas about intervals clearer. I based my answer on the naive interpretation of the notion, and you're right, that's not what you're dealing with.

Now that I realise that Interval Computation is a whole field of mathematics, I'm more inclined to suggest that your module name should somehow express that. Since interval and computation are both generic and already have broad CS usage, I'd lean toward something like Interval::Analysis. Maybe put it in the Math namespace as well, although Math::Interval::Analysis is pretty long. It does seem like The right thing to do though...