“…g z : [a, b] × [c, d] → R, g z (u, v) = g(u, v, z), z ∈ [e, f ], g y : [a, b] × [e, f ] → R, g y (u, w) = g(u, y, w), y ∈ [c, d], g x : [c, d] × [e, f ] → R, g x (v, w) = g(x, v, w), x ∈ [a, b],are convex. Recall the following inequality of Hermite-Hadamard type for coordinated convex function on a rectangular box in R 3 from[15].…”