A = {1, 2}, B = {2, 3}, C = {1, 3}
[b] A × (B ⋂ C) ={(1;3);(2;3)}[/b]
A × C={(1;1};(1;3);(2;1);(2;3)}
C \ B={1;3}\{2;3}={1}
A × (C \ B)={(1;1);(2;1)}
[b](A × C) \ (A × (C \ B)) ={(1;1};(1;3);(2;1);(2;3)}\{(1;1);(2;1)}=
={(1;3);(2;3)}[/b]
Верно