排序方式: 共有37条查询结果,搜索用时 312 毫秒
1.
We show that every arithmetically Cohen-Macaulay two-codimensional subscheme ofP
n can be deformed to a reduced union of two-codimensional linear subvarieties. This problem (classical for curves with the name of Zeuthen problem) was solved for curves by F.Gaeta. 相似文献
2.
Charles Almeida Aline V. Andrade Rosa M. Miró-Roig 《Journal of Pure and Applied Algebra》2019,223(4):1817-1831
Let be a minimal monomial Togliatti system of forms of degree d. In [4], Mezzetti and Miró-Roig proved that the minimal number of generators of lies in the interval . In this paper, we prove that for and , the integer values in cannot be realized as the number of minimal generators of a minimal monomial Togliatti system. We classify minimal monomial Togliatti systems of forms of degree d with or 3n (i.e. with the minimal number of generators reaching the border of the non-existence interval). Finally, we prove that for , and there exists a minimal monomial Togliatti system of forms of degree d with . 相似文献
3.
Rosa M. Miró-Roig 《Rendiconti del Circolo Matematico di Palermo》1938,62(1):153-164
The goal of this paper is to demonstrate that all non-singular rational normal scrolls \(S(a_0,\ldots ,a_k)\subseteq \mathbb P ^N\), \(N =\sum _{i=0}^k(a_i)+k\), (unless \(\mathbb P ^{k+1}=S(0,\ldots ,0,1)\), the rational normal curve \(S(a)\) in \(\mathbb P ^a\), the quadric surface \(S(1,1)\) in \(\mathbb P ^3\) and the cubic scroll \(S(1,2)\) in \(\mathbb P ^4\)) support families of arbitrarily large rank and dimension of simple Ulrich (and hence indecomposable ACM) vector bundles. Therefore, they are all of wild representation type unless \(\mathbb P ^{k+1}\), \(S(a)\), \(S(1,1)\) and \(S(1,2)\) which are of finite representation type. 相似文献
4.
5.
In this paper, we investigate higher rank Brill-Noether problems for stable vector bundles on Hirzebruch surfaces. Using suitable non-splitting extensions, we deal with the non-emptiness. Results concerning the emptiness follow as a consequence of a generalization of Clifford’s theorem for line bundles on curves to vector bundles on surfaces. 相似文献
6.
Juan Migliore Rosa M. Miró-Roig Satoshi Murai Uwe Nagel Junzo Watanabe 《Archiv der Mathematik》2013,101(5):445-454
A homogeneous ideal I of a polynomial ring S is said to have the Rees property if, for any homogeneous ideal ${J \subset S}$ which contains I, the number of generators of J is smaller than or equal to that of I. A homogeneous ideal ${I \subset S}$ is said to be ${\mathfrak{m}}$ -full if ${\mathfrak{m}I:y=I}$ for some ${y \in \mathfrak{m}}$ , where ${\mathfrak{m}}$ is the graded maximal ideal of ${S}$ . It was proved by one of the authors that ${\mathfrak{m}}$ -full ideals have the Rees property and that the converse holds in a polynomial ring with two variables. In this note, we give examples of ideals which have the Rees property but are not ${\mathfrak{m}}$ -full in a polynomial ring with more than two variables. To prove this result, we also show that every Artinian monomial almost complete intersection in three variables has the Sperner property. 相似文献
7.
Rosa M. Miró-Roig 《Algebras and Representation Theory》2014,17(5):1587-1596
In this short note we establish a close relationship between two a priori unrelated problems: (1) the existence of ordinary curves in ? n and, (2) the existence of artinian graded algebras satisfying the Weak Lefschetz Property. 相似文献
8.
Rosa Maria Miró -Roig Helena Soares 《Proceedings of the American Mathematical Society》2008,136(11):3751-3757
A very long-standing problem in Algebraic Geometry is to determine the stability of exceptional vector bundles on smooth projective varieties. In this paper we address this problem and we prove that any exceptional vector bundle on a smooth complete intersection -fold of type with and is stable.
9.
Edoardo Ballico Giorgio Bolondi Philippe Ellia Rosa Maria Mirò -Roig 《Transactions of the American Mathematical Society》1997,349(11):4589-4608
In this paper we show the existence of smooth connected space curves not contained in a surface of degree less than , with genus maximal with respect to the degree, in half of the so-called range A. The main tool is a technique of deformation of stick-figures due to G. Fløystad.
10.
Rosa M. Miró-Roig 《manuscripta mathematica》1986,56(1):11-17
Let 3 be the projective space over an algebraically closed field k and let E be a rank 3 stable reflexive sheaf on 3 such that its restriction to a general plane is stable. The aim of this paper is to give a sharp bound of s= lengthExt
1 (E,G)in terms of the Chern classes of E. 相似文献