intersection(DivisorClassRepresentativeM0nbar,CurveClassRepresentativeM0nbar) -- intersection number of a divisor class and curve class

Synopsis

Function: intersection
Usage:

intersection(D,C)
Inputs:
- D, an instance of the type DivisorClassRepresentativeM0nbar,
- C, an instance of the type CurveClassRepresentativeM0nbar,
Outputs:
- a rational number,

The basic formula for intersecting a boundary divisor with an F-curve is found in Keel and McKernan's paper.

i1 : L1={ {{{2,1},{3},{4},{5}},-2}, {{{1,3},{2},{4},{5}},-7}, {{{1,4},{2},{3},{5}},1}};

i2 : C=curveClassRepresentativeM0nbar(5,L1);

i3 : L2={ {{1,3},1}, {{1,4},1}};

i4 : D=divisorClassRepresentativeM0nbar(5,L2);

i5 : intersection(D,C)

o5 = 6