resultant (version 1.0.0)

principalSubresultants: Principal subresultants of two polynomials

Description

Principal subresultants of two polynomials with rational coefficients.

Usage

principalSubresultants(qspray1, qspray2, var = 1)

Value

If both qspray1 and qspray2 are univariate polynomials, the function returns a vector of bigq rational numbers. Otherwise, it returns a list of qspray polynomials that do not involve the var-th variable.

Arguments

qspray1, qspray2

two qspray polynomials with at most nine variables

var

integer indicating with respect to which variable the subresultants are desired (e.g. 1 for x and 2 for y)

Examples

library(resultant)
x <- qlone(1)
y <- qlone(2)
p <- x^2 * y * (y^2 - 5*x + 6)
q <- x^2 * y * (3*y + 2)
principalSubresultants(p, q, var = 1) # should be 0, 0, non-zero, ...
principalSubresultants(p, q, var = 2) # should be 0, non-zero, ...