2003/01/11 by Alexander Postnikov, Boris Shapiro, Postnikov, Alexander +1 · 3 citations
Computer Science · Mathematics · #05A99 #05C05 #13D02 #13P99 #Combinatorics (math.CO) #Commutative Algebra (math.AC) #Commutative Algebra and Its Applications #FOS: Mathematics #Polynomial and algebraic computation #Topological and Geometric Data Analysis #math.AC #math.CO #msc:05A99 #msc:05C05 #msc:13D02 #msc:13P99
paper · pdf · doi:10.48550/arxiv.math/0301110
33 pages; v2: appendix on sandpiles added, references added, typos corrected; v3: references added
openalex publication_date 2003/01/11 · arxiv created 2003/02/14 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
For a graph G, we construct two algebras, whose dimensions are both equal to the number of spanning trees of G. One of these algebras is the quotient of the polynomial ring modulo certain monomial ideal, while the other is the quotient of the polynomial ring modulo certain powers of linear forms. We describe the set of monomials that forms a linear basis in each of these two algebras. The basis elements correspond to G-parking functions that naturally came up in the abelian sandpile model. These ideals are instances of the general class of monotone monomial ideals and their deformations. We show that the Hilbert series of a monotone monomial ideal is always bounded by the Hilbert series of its deformation. Then we define an even more general class of monomial ideals associated with posets and construct free resolutions for these ideals. In some cases these resolutions coincide with Scarf resolutions. We prove several formulas for Hilbert series of monotone monomial ideals and investigate when they are equal to Hilbert series of deformations. In the appendix we discuss the sandpile model.