Notes on selection rules of canonical differential equations and relative cohomology

A bstract We give an explanation of the d log-form of the coefficient matrix of canonical differential equations using the projection of ( n +1)-d log forms onto n -d log forms. This projection is done using the leading-order formula for intersection numbers. This formula gives a simple way to compute the coefficient matrix. When combined with the relative twisted cohomology, redundancy in computation using the regulator method can be avoided.