Towards certified irreducibility testing of bivariate approximate polynomials

  • Authors:
  • Kosaku Nagasaka

  • Affiliations:
  • Univ. of Tsukuba, Tsukuba City, Ibaraki Pref., 305-8571 Japan

  • Venue:
  • Proceedings of the 2002 international symposium on Symbolic and algebraic computation
  • Year:
  • 2002

Quantified Score

Hi-index 0.00

Visualization

Abstract

Let F(x, u) be a given bivariate polynomial and ε be a small positive number. We consider the approximate factorization of F: find polynomials G, H and ΔF such that F = GH + ΔF and ‖ΔF‖ / ‖F‖= ε, where ‖P‖ denotes 2-norm of polynomial P. At first, we introduce a relation between the irreducibility of F and the singular value of a certain matrix. By this relation and an upper bound of variations of the power-series roots of a bivariate polynomial, we give an algorithm for an absolute irreducibility test of a polynomial whose coefficients are perturbed within a given tolerance. In addition, we give a lower bound for a tolerance of the approximate factorization of a given bivariate polynomial. The lower bound is the necessary magnitude of perturbations which make a given polynomial reducible.