The package contains an implementation for computing determinant of free graded complexes, called detComplex, with several derived methods: listDetComplex, mapsComplex, and minorsComplex. This provides a method for producing universal formulas for any family of schemes, just by combining the resolution(Ideal) (missing documentation) method with detComplex. In Section 2 determinants of free resolutions are treated, as well as a few examples. We recommend to see [Dem84, Jou95, GKZ94, Bus06] for more details on determinants of complexes in elimination theory.
The package also provides a method eliminationMatrix for computing matrices and formulas for different resultants applicable on different families of polynomials, such as the Macaulay resultant (Macaulay) for generic homogeneous polynomials; the residual resultant ('ciResidual' and 'CM2Residual') for generic polynomials having a non empty base locus scheme; the determinantal resultant ('determinantal') for generic polynomial matrices of a given generic rank. For the theory behind those resultants, the reader can refer to [Mac02, Jou91, Cha93, GKZ94, Jou97, CLO98, BEM00, BEM01, Bus01b, Bus06, Bus04].
The goal of this package is to provide universal formulas for elimination. The main advantage of this approach consists in the fact that one can provide formulas for some families of polynomials just by taking determinant to a free resolution. A direct consequence of a universal formula is that it is preserved by base change, in particular it commutes with specialization. A deep study of universal formulas for the image of a map of schemes can be seen in [EH00].
Bibliography:
[BBD12] Nicolás Botbol, Laurent Busé and Manuel Dubinsky. PDF. Package for elimination theory in Macaulay2 (2012).
[BEM00] Laurent Busé, Mohamed Elkadi and Bernard Mourrain, Generalized resultants over unirational algebraic varieties, J. Symbolic Comput. 29 (2000), no. 4-5, 515–526.
[BEM01] Laurent Busé, Mohamed Elkadi and Bernard Mourrain, Resultant over the residual of a complete intersection, Journal of Pure and Applied Algebra 164 (2001), no. 1-2, 35–57.
[Bus01a] Laurent Busé, Residual resultant over the projective plane and the implicitization problem, Internation Symposium on Symbolic and Algebraic Computing (ISSAC), ACM, (2001). Please, see the errata.pdf attached file., pp. 48–55.
[Bus04] Laurent Busé, Resultants of determinantal varieties, J.Pure Appl. Algebra193 (2004), no.1-3, 71–97.
[Bus06] Laurent Busé, Elimination theory in codimension one and applications, (2006).
[Cha93] Marc Chardin, The resultant via a Koszul complex, Computational algebraic geometry (1992), Progr. Math, vol. 109, Birkhäuser Boston, Boston, MA, pp. 29–39.
[CLO98] David Cox, John Little and Donal O’Shea, Using algebraic geometry, Graduate Texts in Mathematics, vol. 185, Springer-Verlag, New York, (1998).
[Dem94] Michel Demazure, Une définition constructive du resultant, Centre de Mathématiques de l’Ecole Polytechnique 2 (1984), no. Notes informelles du calcul formel 1984-1994, 0–23.
[EH00] David Eisenbud and Joe Harris, The geometry of schemes., Graduate Texts in Mathematics. 197. New York, NY: Springer. x, 294 p., (2000).
[GKZ94] Israel M. Gel′fand, Mikhail M. Kapranov and Andrei V. Zelevinsky, Discriminants, resultants, and multidimensional determinants, (1994). Mathematics: Theory & Applications, Birkh ̈auser Boston Inc, Boston, MA.
[Jou91] Jean-Pierre Jouanolou, Le formalisme du résultant, Adv. Math 90 (1991), no. 2, 117–263.
[Jou97] Jean-Pierre Jouanolou, Formes d’inertie et résultant: un formulaire, Adv. Math. 126 (1997), no. 2, 119–250.
[Mac02] Francis S. Macaulay, Some formulae in elimination, Proc. London Math. Soc. 33 (1902), no. 1, 3–27.
This documentation describes version 1.4 of EliminationMatrices.
The source code from which this documentation is derived is in the file EliminationMatrices.m2.