<Li> A is a subset of B, denoted by A ⊆ B, (\ displaystyle A \ subseteq B,) </Li> <Dd> or equivalently <Ul> <Li> B is a superset of A, denoted by B ⊇ A . (\ displaystyle B \ supseteq A .) </Li> </Ul> </Dd> <Ul> <Li> B is a superset of A, denoted by B ⊇ A . (\ displaystyle B \ supseteq A .) </Li> </Ul> <Li> B is a superset of A, denoted by B ⊇ A . (\ displaystyle B \ supseteq A .) </Li>

If a is a subset of b and b is a subset of a