()The order in which the elements of a set are listed is not important. {a, b,c},{a, c, b}, {b, a, c}, {(,,a}, {c, a, b},and {c, b, a} are all representations of the same set. (2) In the listing of the elements of a set, r{a,, b, d} ements aren't allowed. (3)A set can be an element of another set Example: S={{a, b}, {a, b,c}, {d,e}} Note: {a, b,c} is also a set consisting of elements a,b,c. a,b, and c aren't elements 9 of S.(1)The order in which the elements of a set are listed is not important. {a,b,c},{a,c,b},{b,a,c},{b,c,a},{c,a,b},and {c, b, a} are all representations of the same set. (2) In the listing of the elements of a set, repeated elements aren't allowed. (3)Aset can be an element of another set Example: S={{a,b},{a,b,c},{d,e}} Note:{a,b,c} is also a set consisting of elements a,b,c。a,b, and c aren’t elements of S