This file offers two functions: resultant and SubresultantSeq.
Let f and g be two RingElem whose values are in a polynomial ring P.
Let x be the index of an indeterminate from P.
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