Consider set A as
A = {1, 2, 3, 4, 5}
Empty set is the subset of all sets
Subset is a set which contains all elements of the other set
Since empty set has no elements,
it will be the subset of every set
∴ ϕ ⊂ A
Set is the subset of itself
Since, all elements of A are in A,
A is a subset of A
∴ A ⊂ A
