getScrollDegrees -- Computes the degree of a section of a bundle on the scroll ring corresponding to a polynomial in the Cox ring

Synopsis

Usage:
getScrollDegrees(ab',e)
Inputs:
- ab', a list, containing the bidegree of polynomial in the Cox ring
- e, a list, the type of the scroll
Outputs:
- ab, a list, containing the bidegree on the scroll

Computes integers a and b such that H⁰(O_P(E)(aH+bR)) corresponds to basis({a’,b’},Rcox), where Rcox is the Cox ring of the scroll P(E).