coefficient(BasicList,BasicDivisor) -- get the coefficient of an ideal for a fixed divisor

• Function: coefficient

• Usage:

  coefficient(L, D)

• Inputs:
  • L, a basic list, the list of elements in a Grobner basis of a height one prime ideal that we want to find the coefficient of
  • D, an instance of the type BasicDivisor, the divisor in question
• Outputs:
  • a number,

i1 : R = QQ[x,y,u,v]/ideal(x*y-u*v);

i2 : E = divisor(x*u)

o2 = Div(v, x) + Div(u, y) + 2*Div(u, x)

o2 : WeilDivisor on R

i3 : coefficient({u, x}, E)

o3 = 2

i4 : coefficient({x, u}, E)

o4 = 0