1) parity or symmetry, odd function is symmetric about the origin, and even function is symmetric about y axis.

2) Monotonicity, which can be global monotonicity or monotonicity near a cell or a point.

3) The sign or size relation of the function value at some points, and the limit of some points that are not on the function image, such as the function value when X approaches the plus or minus infinity or the end of the open interval.