“…denotes the rounding to the nearest integer (round) operator. , namely t (0,0) (0,0) , t (0,0) (1,0) , t (0,0) (0,1) , t (0,0) (1,1) at each one of the support points, as well as the values of the partial derivatives up to the 1st degree: t (0,1) (0,0) , t (0,1) (1,0) , t (0,1) (0,1) , t (0,1) (1,1) , t (1,0) (0,0) , t (1,0) (1,0) , t (1,0) (0,1) , t (1,0) (1,1) , t (1,1) (0,0) , t (1,1) (1,0) , t (1,1) (0,1) , t (1,1) (1,1) , the following conditions must hold:…”