2003/10/20 by Anargyros Katsabekis, Katsabekis, Anargyros, Marcel Morales +3
Mathematics · #13F55 #14M25 #Algebraic Geometry (math.AG) #Commutative Algebra (math.AC) #FOS: Mathematics #math.AC #math.AG #msc:13F55 #msc:14M25
paper · pdf · doi:10.48550/arxiv.math/0310313
arxiv created 2003/10/20 · arxiv updated 2009/12/01
In this article we associate to every lattice ideal IL,ρ⊂ K[x1,..., xm] a cone σ and a graph Gσ with vertices the minimal generators of the Stanley-Reisner ideal of σ. To every polynomial F we assign a subgraph Gσ(F) of the graph Gσ. Every expression of the radical of IL,ρ, as a radical of an ideal generated by some polynomials F1,..., Fs gives a spanning subgraph of Gσ, the ∪i=1s Gσ(Fi). This result provides a lower bound for the minimal number of generators of IL,ρ and therefore improves the generalized Krull's principal ideal theorem for lattice ideals. But mainly it provides lower bounds for the binomial arithmetical rank and the A-homogeneous arithmetical rank of a lattice ideal. Finally we show, by a family of examples, that the bounds given are sharp.