There are few exceptions for which an interval evaluation of an expression cannot be computed for some ranges of the unknowns that appear in the expression. Namely the following problems may occur when intervals are involved:

- denominator that may include 0
- argument of square should be positive
- argument of arcsin and arccos should be included in [-1,1]
- argument of log,ln,log10 should be positive
- argument of arccosh should be greater than 1
- argument of arctanh cannot have an intersection with the interval [-1,1]
- argument of where is not an integer should be positive
- argument of should not be too large to avoid overflow problem.

Jean-Pierre Merlet 2012-12-20