In other words; When B=A, b is a subset of a.
When b is less than a, it is proper subset.
2. Because the rhombus is a parallelogram and the parallelogram is not a rhombus, it can be seen that the parallelogram is greater than or equal to the rhombus. In this series,
Use tolerance to express this relationship. If a contains b, it can be understood that a is greater than or equal to B.
3. For example, 1