... {x 1, x 2, , x n }, then sup (X) = x 1¦ x 2 ¦ ¦ x n X For a point set X with total order , x 0 = X Ô x x0, x X \ {x 0}inf (X) If X , then inf (X) = the infimum of X . If X = {x 1, x 2, ... X ) Y} X × YIf X, Y , then X × Y = { (x, y) : x X and y Y} -X If X , then -X = { -x : x X} If X , then = {z : z and z X} sup (X) If X , then sup (X) = the supremum of X. If X = {x 1, ... defined by k ³ a = { (x, c (x) ) : c (x) = k ³ a (x) ,x X} .abLet a, b ; ab = { (x, c (x) ) : c (x) = a (x) b (x) , x X} .logbaLet a, b logba = { (x, c (x) ) : c (x) = logb (x) a (x) , x X} .a*...