Start with a rational/real divisor, we form a new divisor whose coefficients are obtained by taking the ceiling function
i1 : R = QQ[x, y, z] / ideal(x *y - z^2) o1 = R o1 : QuotientRing |
i2 : D = divisor({1/2, 4/3}, {ideal(x, z), ideal(y, z)}, CoeffType => QQ) o2 = 1/2*Div(x, z) + 4/3*Div(y, z) of R o2 : QDiv |
i3 : ceilingDiv( D ) o3 = 1*Div(x, z) + 2*Div(y, z) of R o3 : WDiv |