Let A = {ϕ {ϕ}, 1, {1, ϕ}, 2}. Which of the following are true ?
(i) ϕ ϵ A (ii) {ϕ} ϵ A
(iii) {1} ϵ A (iv) {2, ϕ} ⊂ A
(v) 2 ⊂ A (vi) {2, {1}} ⊈ A
(vii) {{2}, {1}}, ⊈ A
(viii) { ϕ, {ϕ} , {1, ϕ}} ⊂ A
(ix) {{ ϕ}} ⊂ A.
(i) True, ∵ ϕ indeed belongs to A.
(ii) True, ∵ {ϕ} is an element of A.
(iii) False, ∵ {1} is not an element of A.
(iv) True,
∵ {2, ϕ} is a subset of A.
(v) False,
∵ 2 is not a subset of A, it is an element of A.
(vi) True, ∵ {2, {1}} is not a subset of A.
(vii) True, ∵ {2, {1}} is not a subset of A.
(viii) True, ∵ {ϕ, {ϕ}, {1, ϕ}} is a subset of A.
(ix) True, ∵ {{ϕ }} is a subset of A.