In high school mathematics, under what circumstances can an interval not be represented by intersection and union?
The monotone interval is expressed as b)∩(b a, b), (b, +∞) or (a, b) and (b, +∞), because the monotone interval is that the function is monotone on (a, b) and monotone on (b, +∞), but because the value of point b is not desirable, (a, ∞).