Generally speaking, some identifiable different objects are regarded as a whole, that is, the whole is a set (or collection) composed of all these objects; Each object that constitutes a set is called an element (or member) of this set.

Exchange law: a ∩ b = b ∩ a.

A∪B=B∪A

Binding law: A ∪ (B ∪ C) = (A ∪ B) ∪ C c.

A∩(B∩C)=(A∩B)∩C

The law of distributive duality: A∩(B∪C)=(A∪B)∩(A∪C)

A ∪( B∪C)=(A∪B)∪( A∪C)

Duality law: (a∪b)c = a c∪b c

(A∩B)^C=A^C∪B^C

Identity: a ∪ φ = a

A∩U=A

Complement law: A∪A'=U

A∩A ' =φ

Law of involution: (A')'=A

Law of idempotent: A∪A=A

A∩A=A

Zero consistency: A∪U=U

A∩U=A