next | previous | forward | backward | up | top | index | toc | Macaulay2 web site
Divisor :: BasicDiv + BasicDiv

BasicDiv + BasicDiv -- Sum two divisors.

Synopsis

Description

Returns the sum of two divisors. For example it can add Weil divisors
i1 : R = QQ[x, y, z]

o1 = R

o1 : PolynomialRing
i2 : D1 = divisor({1, 2, 1, 3, 8}, {ideal(x), ideal(y), ideal(z), ideal(y), ideal(y)})

o2 = 1*Div(z) + 13*Div(y) + 1*Div(x) of R

o2 : WDiv
i3 : D2 = divisor({-2, 3, -5}, {ideal(z), ideal(y), ideal(x)})

o3 = 3*Div(y) + -2*Div(z) + -5*Div(x) of R

o3 : WDiv
i4 : D1 + D2

o4 = -1*Div(z) + 16*Div(y) + -4*Div(x) of R

o4 : WDiv
or it can add divisors of different types
i5 : R = QQ[x]

o5 = R

o5 : PolynomialRing
i6 : D1 = divisor({3}, {ideal(x)})

o6 = 3*Div(x) of R

o6 : WDiv
i7 : D2 = divisor({3/2}, {ideal(x)}, CoeffType=>QQ)

o7 = 3/2*Div(x) of R

o7 : QDiv
i8 : D3 = divisor({1.333}, {ideal(x)}, CoeffType=>RR)

o8 = 1.333*Div(x) of R

o8 : RDiv
i9 : D1+D2

o9 = 9/2*Div(x) of R

o9 : QDiv
i10 : D1+D3

o10 = 4.333*Div(x) of R

o10 : RDiv
i11 : D2+D3

o11 = 2.833*Div(x) of R

o11 : RDiv