Union and Intersection
If A and B are disjoint sets, then
From this, one can show that in general the cardinalities of unions and intersections are related by
Read more about this topic: Cardinality
Famous quotes containing the words union and/or intersection:
“If the Union is once severed, the line of separation will grow wider and wider, and the controversies which are now debated and settled in the halls of legislation will then be tried in fields of battle and determined by the sword.”
—Andrew Jackson (1767–1845)
“You can always tell a Midwestern couple in Europe because they will be standing in the middle of a busy intersection looking at a wind-blown map and arguing over which way is west. European cities, with their wandering streets and undisciplined alleys, drive Midwesterners practically insane.”
—Bill Bryson (b. 1951)