intersection index of and , two cycles lying on a closed
surface. if and do not intersect.
Otherwise gets an additive contribution from every
intersection point. This contribution is if the basis of
the tangent vectors of the and cycles
(§21.7(i)) at the point of intersection is
positively oriented; otherwise it is .
►Table 3.5.20 gives the results of applying the composite trapezoidal rule (3.5.2) with step size ; indicates the number of function values in the rule that are larger than (we exploit the fact that the integrand is even).