Which of the following is not true for two non-empty sets A and B?
If A ⊆ B and B ⊆ A, then A = B.
For every set A, empty set ϕ and A itself, are the subsets.
If A ⊂ B and A ≠B, then B is called superset of A.
If A ⊂ B and A ≠B, then A is called superset of B.
Let A and B be two sets. If A ⊂ B and A≠B, then A is called a proper subset of B and B is called superset of A.