In Collection theory, a Collection union (union) is a set of all the elementals of those Collections that make up a Collection and contain no other elementals.

For both

For both Given Collection A, B, the collection consisting of all elementals belonging to Collection A or belonging to Collection B (the collection consisting of all elementals of both Collections combined) is called union, denote A ∪ B, read as "Collection ∪ B", and read as "Collection ∪ B". ) is called union, denote A∪B, read as "A and B". It is denoted by notation, i.e.: A∪B={xIx∈A or x∈B}

progression Nature number together formulas : S(n) = 1³ + ... + n³ = [n/2(1 + n)]²