SparsePolyOps-RealRadical

© 2017 John Abbott, Anna M. Bigatti

GNU Free Documentation License, Version 1.2

CoCoALib Documentation Index

Examples

User documentation

Operations

There are two functions for polynomials with coefficients in RingQQ():

  • HasRealRoot3(f) tests quickly and heuristically whether f has real roots; a return result of uncertain3 means f may or may not have real roots
  • RealRadical(f) computes a multiple of the real radical of f

The function HasRealRoot3 is reliable for univariate polynomials.

Maintainer documentation

Implementation is relatively straightforward.

Bugs, shortcomings and other ideas

It is a shame that RealRadical has to use factorization; is there a better way?

Perhaps better heuristics for the multivariate case can be added: maybe test whether the multivariate can be mapped down to univariate with real roots (by setting all-but-1 indets to -1, 0 or +1)?

Main changes

  • 2017
    • November (v0.99561): first release -