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Using basic properties of perverse sheaves, we give new upper bounds for compactly supported Betti numbers for arbitrary affine varieties in $\mathbb{A}^n$ defined by $r$ polynomial equations of degrees at most $d$. As arithmetic…

Algebraic Geometry · Mathematics 2025-01-23 Daqing Wan , Dingxin Zhang

We show that the long exact sequence for K-groups of Leavitt path algebras deduced by Ara, Brustenga, and Cortinas extends to Leavitt path algebras of countable graphs with infinite emitters in the obvious way. Using this long exact…

K-Theory and Homology · Mathematics 2015-03-27 James Gabe , Efren Ruiz , Mark Tomforde , Tristan Whalen

We extend a result of Caviglia and Sbarra to a polynomial ring with base field of any characteristic. Given a homogeneous ideal containing both a piecewise lex ideal and an ideal generated by powers of the variables, we find a lex ideal…

Commutative Algebra · Mathematics 2021-02-25 Christina Jamroz , Gabriel Sosa

Let $T$ be a perfect binary tree and $I$ be its edge ideal in the polynomial ring $S$. We determine the vertex cover number, independent number, and establish the recursive formula to compute the number of minimal vertex covers. As a…

Commutative Algebra · Mathematics 2025-09-25 Nguyen Thu Hang , Tran Duc Dung , Do Van Kien

We provide an explicit description of the K-classes of higher Kazhdan projections in degrees greater than 0 for specific free product groups and Cartesian product groups. Employing this description, we obtain new calculations of Lott's…

Operator Algebras · Mathematics 2026-05-27 Sanaz Pooya , Hang Wang

Let $K\geq 2$ be a natural number and $a_i,b_i\in\mathbb{Z}$ for $i=1,\ldots,K-1$. We use the large sieve to derive explicit upper bounds for the number of prime $k$-tuplets, i.e., for the number of primes $p\leq x$ for which all $a_ip+b_i$…

Number Theory · Mathematics 2024-09-09 Thomas Dubbe

Belyi's Theorem states that a Riemann surface, X, as an algebraic curve is defined over an algebraic closure of the rationals if and only if there exists a holomorphic function taking X to the Riemann sphere with at most three critical…

Number Theory · Mathematics 2015-03-19 Jose Rodriguez

The goal of this paper is to ameliorate the sufficients conditions, already established by the first author so that the sum of the numbers of Betti, of 1-connected rational finite CW-complex, is higher than the dimension of his $\mathbb…

Algebraic Topology · Mathematics 2007-12-26 Mohamed Rachid Hilali , My Ismail Mamouni

For an ideal $I$ in a regular local ring or a graded ideal $I$ in the polynomial ring we study the limiting behavior of the Betti numbers of S/I^k as k goes to infinity. By Kodiyalam's result it is known that in each homological degree the…

Commutative Algebra · Mathematics 2009-10-20 Juergen Herzog , Volkmar Welker

We study the hyperbolicity of singular quotients of bounded symmetric domains. We give effective criteria for such quotients to satisfy Green-Griffiths-Lang's conjectures in both analytic and algebraic settings. As an application, we show…

Algebraic Geometry · Mathematics 2018-10-01 Benoit Cadorel , Erwan Rousseau , Behrouz Taji

We present an extremely elementary construction of the simple Lie algebras over the complex numbers in all of their minuscule representations, using the vertices of various polytopes. The construction itself requires no complicated…

Representation Theory · Mathematics 2007-05-23 R. M. Green

Let I be a homogeneous ideal in a polynomial ring P over a field. By Macaulay's Theorem, there exists a lexicographic ideal L=Lex(I) with the same Hilbert function as I. Peeva has proved that the Betti numbers of P/I can be obtained from…

Commutative Algebra · Mathematics 2009-04-08 Maria Evelina Rossi , Leila Sharifan

Constructions are given of Noetherian maximal orders that are finitely presented algebras over a field K, defined by monomial relations. In order to do this, it is shown that the underlying homogeneous information determines the algebraic…

Rings and Algebras · Mathematics 2007-11-05 Isabel Goffa , Eric Jespers , Jan Okninski

Let C be a smooth projective algebraic curve of genus g over the finite field F_q. A classical result of H. Martens states that the Brill-Noether locus of line bundles L in Pic^d C with deg L = d and h^0(L) >= i is of dimension at most…

Algebraic Geometry · Mathematics 2019-08-08 Kamal Khuri-Makdisi

On the category of bounded complexes of finitely generated free squarefree modules over the polynomial ring S, there is the standard duality functor D = Hom_S(-, omega_S) and the Alexander duality functor A. The composition AD is an…

Commutative Algebra · Mathematics 2016-09-30 Gunnar Floystad

A foundational principle in the study of modules over standard graded polynomial rings is that geometric positivity conditions imply vanishing of Betti numbers. The main goal of this paper is to determine the extent to which this principle…

Commutative Algebra · Mathematics 2024-02-21 Michael K. Brown , Daniel Erman

We give estimates for the zero loci of Bernstein-Sato ideals. An upper bound is proved as a multivariate generalisation of the upper bound by Lichtin for the roots of Bernstein-Sato polynomials. The lower bounds generalise the fact that…

Algebraic Geometry · Mathematics 2023-01-13 Nero Budur , Robin van der Veer , Alexander Van Werde

We bound from above the expected total Betti number of a high degree random real hypersurface in a smooth real projective manifold. This upper bound is deduced from the equirepartition of critical points of a real Lefschetz pencil…

Algebraic Geometry · Mathematics 2011-07-13 Damien Gayet , Jean-Yves Welschinger

We prove a tight lower bound on the Betti numbers of tree and forest ideals and a tight upper bound on certain graded Betti numbers of squarefree monomial ideals.

Commutative Algebra · Mathematics 2008-09-02 Michael Goff

We are interested in algebraic properties of empty lattice simplices $\Delta$, that is, $d$-dimensional lattice polytopes containing exactly $d+1$ points of the integer lattice $\mathbb{Z}^d$. The cyclicity rank of $\Delta$ is the minimal…

Combinatorics · Mathematics 2025-03-10 Lukas Abend , Matthias Schymura