Finds the effective divisor D such that O(D) is isomorphic to I and so that f in I corresponds to 1 in O(D).
i1 : R = ZZ/7[x] o1 = R o1 : PolynomialRing
i2 : idealWithSectionToDivisor(x^2, ideal(x)) o2 = 1*Div(x) of R o2 : WDiv