Factored Notation for Interval I/O

This note addresses the input and output of intervals in the sense of interval arithmetic and interval constraints. The most obvious, and so far most widely used notation, for intervals has drawbacks that we remedy with a new notation that we propose to call factored notation. It is more compact and allows one to find a good trade-off between interval width and ease of reading. We describe how such a trade-off can be based on the information yield (in the sense of information theory) of the last decimal shown.