5. Let u be a universe of persons and let ParentOf, MotherOf, FatherOf, DaughterOf, and SonOf be relations over U such that ParentOf (x, y) if z is a parent of y, MotherOf (z, y) if z is the mother of y, FatherOf (x, y) if r is the father of y, DaughterOf (x,y) if x is the daughter of y, and SonOf (x, y) if x is the son of y, respectively. 1. Write an expression of operations on these relations to find the relation of pairs (x, y) such that x is a great-grandson of y. 2. Write an expression of operations on these relations to find the relation of pairs (x, y) such that x and y are not siblings