SUBSET

A set A is a subset of a set B if every element of A is also an element of B.Such a relation between sets is denoted by A⊆B.

PROPER SUBSET

If a set A is a subset of a set B and is not equal to B, then we call A a PROPER SUBSET of B, and write A ⊂ B

IMPROPER SUBSET

An "Improper Subset" is a subset which can be equal to the original set.It is notated by the symbol ⊆ which can be interpreted as "IS A PROPER SUBSET Or IS EQUAL TO".