MA 141 Study Guide - Final Guide: Infimum And Supremum, New Zealand, Natural Number
Document Summary
Def: a set is a collection of objects. If x is an object in a set s, we say x is an element of. If every element of a set a is also an element of a set b, we say a is a subset of b and write a b. Two sets are equal if they have exactly the same elements. A b, b a a = b. Def: the union of two sets is the set containing all elements of either set. A b = {1, 2, 3, 4} Def: the intersection of two sets is the set containing the elements that are in both sets. Def: the di erence of two sets is the set containing the elements in one set but not in the other. Ex: a = {1, 2} and b = {2, 3, 4}. A \ b = a b = {1}, b \ a = b a = {3, 4}
