Set Operations
- B ⊂ A (B is a subset of A) if every element of B is an element of A. Equivalently A ⊃ B (A is a superset of B)
- A ∩ B = {x | x ∈ A ∧ x ∈ B } -- intersection of A and B
- A ∪ B = {x | x ∈ A ∨ x ∈ B } -- union of A and B
- If A ⊂ X , AC = X \ A = { x | x ∈ X, x ∉ A } -- complement of A in X
