Gap.__invert__ makes poor assumptions about the bounds of a Gaps generic type. It's better not to make any assumptions and remove this operator. PositiveInfinity and NegativeInfinity are also removed with this change. Gaps can still be inverted "by hand", e.g. my_gaps ^ Gaps([some_smallest_value < x, x < some_largest_value]).
Var is now public. Useful if x is already in your namespace.