Question

Why null set is sub set of all set??????????????????

Answer 1

It's usually called the empty set and denoted as ∅. It is a subset of every other set since every element in it is an element of every other set

Answer 2

Answer:

Null Set also remarked as 'Empty set' or 'Void set', generally represented as "Φ" (Phi) or "{ }" (empty braces) is a subset of all sets.

This is because every element in a null set is an element of every other set.

But we generally neglect it to be represented and generally represent while finding the number of power sets of an element, which is of the form 2ⁿ.

E.g. Let, set 'S'={1}

Using the above information;

n[P(S)]=2

i.e., P(S)={ Φ, {1} }

=> Φ ⊂ S