Find the absolute minimum and absolute maximum of the function $f(x,y) = xy - 2 y - 4 x + 8$ on the region on or above $y = x^2$ and on or below $y = 7$ and list the points where they occur.

If the absolute min or max is attained at multiple points list them all, separated by commas.

Absolute minimum value:
attained at .

Absolute maximum value:
attained at .