Assume that "X" is a normal integral separated scheme of finite type over a field. Let "D" be a Weil divisor. Then formula_20 is a rank one reflexive sheaf, and since formula_20 is defined as a subsheaf of formula_32 it is a fractional ideal sheaf (see below). Conversely, every rank one reflexive sheaf corresponds to a Weil divisor: The sheaf can be restricted to the regular locus, where it becomes free and so corresponds to a Cartier divisor (again, see below), and because the singular locus has codimension at least two, the closure of the Cartier divisor is a Weil divisor.