intersected with a union c is a subset of a union. A union b is a set of all elements in a that are n't in b it can be thought of as like subtracting b from a i 'll call a minus b for the rest of the video. a equals a set containing 1 2 3 4 4 and 5 and b is the set containing 2 4 6 and 8 then a minus b is six and eight if b is a subset of a the set is called the complement of a with respect to a. The complement negates the predicate with our set builder notation. De morgan 's laws say that th...