Show that A∩B=A∩C need not imply B=C.
Let A = {1, 2, 3, 4}, B = {2, 3, 4, 5, 6}, C = {2, 3, 4, 9, 10}.
∴ A∩B = {1, 2, 3, 4} ∩ {2, 3, 4, 5, 6}
= {2, 3, 4}
A∩C = {1, 2, 3, 4} ∩ {2, 3, 4, 9, 10}
Now we have
A∩B=A∩C
But B≠C.
Show that A intersection B is equal to A intersection C need not imply B=C
For three sets A, B and C, show that
(i) A∩B=A∩C need not imply B = C.
(ii) A⊂B⇒C−B⊂C−A