A set is a collection of objects that have something in common or follow a rule. The objects in the set are called its elements. Set notation uses curly braces, with elements separated by commas.
For example, Q = {2, 4, 6, 8}
Some of the common symbols are listed with examples below:
SymbolMeaningExample{}Set: a collection of elements{1,2,3,4}A∪BUnion: in A or B(or both)C∪D={1,2,3,4,5}A∩BIntersection: in both A and BC∩D={3,4}A⊆BSubset: A has some (or all) elements of B{3,4,5}⊆DA⊂BProper subset: A has some elements of B{3,5}⊂DA/⊂BNot a Subset: A is not a subset of B{1,6}/⊂CA⊇BSuperset: A has same elements as B, or more{1,2,3}⊇{1,2,3}A⊃BProper Superset: A has B′s elements and more{1,2,3,4}⊃{1,2,3}A/⊃BNot a Superset: A is not a superset of B{1,2,6}/⊃{1,9}AcComplement: elements not in ADc={1,2,6,7}WhenU={1,2,3,4,5,6,7}A−BDifference: in A but not in B{1,2,3,4}−{3,4}={1,2}a∈AElement of: a is in A3∈{1,2,3,4}b∈ANot element of: b is not in A6∈{1,2,3,4}ϕEmpty set={}{1,2}∩{3,4}=ϕ