Cayley-Dixon projection operator for multi-univariate composed polynomials

• Autores: Arthur D. Chtcherba, D. Kapur, Manfred Minimair
• Localización: Journal of symbolic computation, ISSN 0747-7171, Vol. 44, Nº 8, 2009, págs. 972-999
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The Cayley�Dixon formulation for multivariate projection operators (multiples of resultants of multivariate polynomials) has been shown to be efficient (both experimentally and theoretically) for simultaneously eliminating many variables from a polynomial system. In this paper, the behavior of the Cayley�Dixon projection operator and the structure of Dixon matrices are analyzed for composed polynomial systems constructed from a multivariate system in which each variable is substituted by a univariate polynomial in a distinct variable. Under some conditions, it is shown that a Dixon projection operator of the composed system can be expressed as a power of the resultant of the outer polynomial system multiplied by powers of the leading coefficients of the univariate polynomials substituted for variables in the outer system. A new resultant formula is derived for systems where it is known that the Cayley�Dixon construction does not contain any extraneous factor. The complexity of constructing Dixon matrices and roots at toric infinity of composed polynomials is analyzed.