Title
Computing syzygies in finite dimension using fast linear algebra
Abstract
We consider the computation of syzygies of multivariate polynomials in a finite-dimensional setting: for a K[X1,…,Xr]-module M of finite dimension D as a K-vector space, and given elements f1,…,fm in M, the problem is to compute syzygies between the fi’s, that is, polynomials (p1,…,pm) in K[X1,…,Xr]m such that p1f1+⋯+pmfm=0 in M. Assuming that the multiplication matrices of the r variables with respect to some basis of M are known, we give an algorithm which computes the reduced Gröbner basis of the module of these syzygies, for any monomial order, using O(mDω−1+rDωlog(D)) operations in the base field K, where ω is the exponent of matrix multiplication. Furthermore, assuming that M is itself given as M=K[X1,…,Xr]n∕N, under some assumptions on N we show that these multiplication matrices can be computed from a Gröbner basis of N within the same complexity bound. In particular, taking n=1, m=1 and f1=1 in M, this yields a change of monomial order algorithm along the lines of the FGLM algorithm with a complexity bound which is sub-cubic in D.
Year
DOI
Venue
2020
10.1016/j.jco.2020.101502
Journal of Complexity
Keywords
DocType
Volume
Gröbner basis,Syzygies,Complexity,Fast linear algebra
Journal
60
ISSN
Citations 
PageRank 
0885-064X
0
0.34
References 
Authors
0
2
Name
Order
Citations
PageRank
Vincent Neiger1397.22
Schost Éric200.34