This function is an even function about the Y axis, and there are two monotonous intervals in the domain.

Its left interval (negative infinity, 0) decreases monotonously, x is a non-positive real number, y is a non-positive real number,

Obviously, this interval cannot satisfy the second condition.

Its right interval monotonically decreases, satisfying the second condition, a = b 2+m, b = a 2+m, m.

The equations are difficult to solve, but the range is within the above range, so it is unnecessary to go into details.

To sum up, the solution function y = x 2+m has a "hedging" interval, and the range of m is: m.

Note: When doing this complicated big problem, we must always pay attention to the questions to be asked in the stem. Sometimes complex situations only need to be considered and analyzed, and no specific solutions are needed.