A modular GCD algorithm over number fields presented with multiple extensions

  • Authors:
  • Mark van Hoeij;Michael Monagan

  • Affiliations:
  • Florida State University, Tallahassee, FL;Simon Fraser University, Burnaby, B.C. Canada

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

Quantified Score

Hi-index 0.00

Visualization

Abstract

We consider the problem of computing the monic gcd of two polynomials over a number field L = ℚ(α1,…,αn). Encarnacion, Langemyr and McCallum have already shown how Brown's modular GCD algorithm for polynomials over ℚ can be modified to work for ℚ(α).Our first contribution is an extension of Encarnacion's modular GCD algorithm to the case n 1 without converting to a single field extension. Our second contribution is a proof that it is not necessary to test if p divides the discriminant. This simplifies the algorithm; it is correct without this test.Our third contribution is the design of a data structure for representing multivariate polynomials over number fields with multiple field extensions. We have a complete implementation of the modular GCD algorithm using it. We provide details of some practical improvements.