The Depth of an Ideal with a given Hilbert Function
نویسندگان
چکیده
Let A = K[x1, . . . , xn] denote the polynomial ring in n variables over a field K with each deg xi = 1. Let I be a homogeneous ideal of A with I 6= A and HA/I the Hilbert function of the quotient algebra A/I. Given a numerical function H : N → N satisfying H = HA/I for some homogeneous ideal I of A, we write AH for the set of those integers 0 ≤ r ≤ n such that there exists a homogeneous ideal I of A with HA/I = H and with depthA/I = r. It will be proved that one has either AH = {0, 1, . . . , b} for some 0 ≤ b ≤ n or |AH | = 1.
منابع مشابه
Topics on the Ratliff-Rush Closure of an Ideal
Introduction Let be a Noetherian ring with unity and be a regular ideal of , that is, contains a nonzerodivisor. Let . Then . The :union: of this family, , is an interesting ideal first studied by Ratliff and Rush in [15]. The Ratliff-Rush closure of is defined by . A regular ideal for which is called Ratliff-Rush ideal. The present paper, reviews some of the known prop...
متن کاملAn extended multidimensional Hardy-Hilbert-type inequality with a general homogeneous kernel
In this paper, by the use of the weight coefficients, the transfer formula and the technique of real analysis, an extended multidimensional Hardy-Hilbert-type inequality with a general homogeneous kernel and a best possible constant factor is given. Moreover, the equivalent forms, the operator expressions and a few examples are considered.
متن کاملResults on Generalization of Burch’s Inequality and the Depth of Rees Algebra and Associated Graded Rings of an Ideal with Respect to a Cohen-Macaulay Module
Let be a local Cohen-Macaulay ring with infinite residue field, an Cohen - Macaulay module and an ideal of Consider and , respectively, the Rees Algebra and associated graded ring of , and denote by the analytic spread of Burch’s inequality says that and equality holds if is Cohen-Macaulay. Thus, in that case one can compute the depth of associated graded ring of as In this paper we ...
متن کاملResults on Hilbert coefficients of a Cohen-Macaulay module
Let $(R,m)$ be a commutative Noetherian local ring, $M$ a finitely generated $R$-module of dimension $d$, and let $I$ be an ideal of definition for $M$. In this paper, we extend cite[Corollary 10(4)]{P} and also we show that if $M$ is a Cohen-Macaulay $R$-module and $d=2$, then $lambda(frac{widetilde{I^nM}}{Jwidetilde{I^{n-1}M}})$ does not depend on $J$ for all $ngeq 1$, where $J$ is a minimal ...
متن کاملLocal Equations for the Toric Hilbert Scheme
We obtain local equations for the toric Hilbert scheme, which parametrizes all ideals with the same multigraded Hilbert function as a given toric ideal. We also prove a conjecture of Sturmfels’ providing a criterion for an ideal to have such a Hilbert function.
متن کامل