ab', a list, containing the bidegree in the Cox ring
Description
This function computes integers a' and b' such that $H^0(O_{P(E)}(aH+bR))$ corresponds to basis($\{a',b'\}$,S), where S is the Cox ring of the scroll $P(E)$.
See also
scrollDegrees -- Computes the degree of a section of a bundle on the scroll ring corresponding to a polynomial in the Cox ring