Question

How to prove that every set is a subset of it's own ?

Answer 1

Yes, a set is always considered a subset of itself, a proper subset, however, cannot contain all of the elements of its parent set !

Answer 2

Answer:

Suppose ∅⊊A where A is a set. So it exists an element x∈∅ such that x∉A wich is absurd because ∅ does not have any elements by definition.