Cartesian product of sets
Sets, relations and functions · Mathematics
Study notes
Q: A = {1, 2}, B = {x, y}. Write A x B and B x A. A x B = {(1,x), (1,y), (2,x), (2,y)} - 4 pairs. B x A = {(x,1), (x,2), (y,1), (y,2)} - different pairs! A x B ≠ B x A.