This file offers 3 functions: discriminant, resultant and SubresultantSeq.
Let f and g be two RingElem values in a polynomial ring P.
Let x be the index of an indeterminate from P.
discriminant(f) -- f returns a RingElem (in the coefficient ring) being the discriminant of univariate f.
resultant(f,g) -- f,g returns a RingElem (in the coefficient ring) being the resultant of univariate f and g.
discriminant(f,x) -- returns a RingElem (in the same ring as f) being the discriminant of f wrt x.
resultant(f,g,x) -- returns a RingElem being the resultant of f and g with respect to the indeteminate x.
SubresultantSeq(f,g,x) -- returns a vector<RingElem> being the subresultant sequence of f and g with respect to the indeteminate x.
Surely a simple rather than fast impl.
Must coeffs be rational?
2019