Ara es mostren els items 1-18 de 18

    • An example of a non acyclic Koszul complex of a module 

      Planas Vilanova, Francesc d'Assís (2000)
      Article
      Accés obert
    • Bass numbers of local cohomology of cover ideals of graphs 

      Álvarez Montaner, Josep; Sohrabi, Fatemeh (2020)
      Article
      Accés obert
      We develop splitting techniques to study the Lyubeznik numbers of cover ideals of graphs which allow us to describe them for large families of graphs including forests, cycles, wheels and cactus graphs. More generally, we ...
    • Characteristic cycle of local cohomology modules of monomial ideals II 

      Álvarez Montaner, Josep (2003)
      Article
      Accés obert
    • Characteristic cycles of local cohomology modules of monomial ideals 

      Álvarez Montaner, Josep (1998)
      Article
      Accés obert
      By using the theory of D-modules we express the characteristic cycle of a local cohomology module supported on a monomial ideal in terms of conormal bundles relative to a subvariety. As a consequence we can decide when a ...
    • Characteristic cycles of localizations: algorithmic approach 

      Álvarez Montaner, Josep; Leykin, Anton (2004)
      Article
      Accés obert
      For a polynomial ring R = k[x1, ..., xn], we present an algorithm for computing the characteristic cycle of the localization Rf for any nonzero polynomial f ∈ R. The approach is useful to answer certain questions regarding ...
    • Ideals of Herzog-Northcott type 

      Planas Vilanova, Francesc d'Assís; O'Carroll, Liam (2011-01-19)
      Article
      Accés obert
      This paper takes a new look at ideals generated by 2×2 minors of 2×3 matrices whose entries are powers of three elements not necessarily forming a regular sequence. A special case of this is the ideals determining monomial ...
    • Linearization of local cohomology modules 

      Álvarez Montaner, Josep; Zarzuela Armengou, Santiago (American Mathematical Society, 2003)
      Capítol de llibre
      Accés obert
      The aim of this work is to describe the linear structure of regular holonomic $\mathcal D$-modules with support a normal crossing with variation zero introduced in [Local cohomology, arrangements of subspaces and monomial ...
    • Local cohomology, arrangement of subspaces and monomial ideals 

      Álvarez Montaner, Josep; García López, Ricardo; Zarzuela Armengou, Santiago (2000)
      Article
      Accés obert
    • Noetherian rings of low global dimension and syzygetic prime ideals 

      Planas Vilanova, Francesc d'Assís (2021-02-01)
      Article
      Accés obert
      Let R be a Noetherian ring. We prove that R has global dimension at most two if, and only if, every prime ideal of R is of linear type. Similarly, we show that R has global dimension at most three if, and only if, every ...
    • Normal transversality and uniform bounds 

      Planas Vilanova, Francesc d'Assís (1999)
      Article
      Accés obert
    • On the module of effective relations of a standard algebra 

      Planas Vilanova, Francesc d'Assís (1996)
      Article
      Accés obert
    • On the vanishing and non-rigidity of the André-Quillen (co)homology 

      Planas Vilanova, Francesc d'Assís (1996)
      Article
      Accés obert
      Let I be an ideal of a commutative ring A, B=A/I. Given n>=2, we characterize the vanishing of the André-Quillen homology modules H_{p}(A,B,W) for all $B$-module $W$ and for all p, 2<=p<=n, in terms of some canonical ...
    • Poincaré series of multiplier and test ideals 

      Álvarez Montaner, Josep; Núñez-Betancourt, Luis (2022-04-29)
      Article
      Accés obert
      We prove the rationality of the Poincaré series of multiplier ideals in any dimension thus extending the main results for surfaces of Galindo and Monserrat and Alberich-Carramiñana et al. Our results also hold for Poincaré ...
    • Pruned cellular free resolutions of monomial ideals 

      Álvarez Montaner, Josep; Fernández Ramos, Óscar; Gimenez, Philippe (2020-01-01)
      Article
      Accés obert
      Using discrete Morse theory, we give an algorithm that prunes the excess of information in the Taylor resolution and constructs a new cellular free resolution for an arbitrary monomial ideal. The pruned resolution is not ...
    • Rings of weak dimension 1 and syzygetic ideals 

      Planas Vilanova, Francesc d'Assís (1996)
      Article
      Accés obert
      We prove that rings of weak dimension one are the rings with all (three-generated) ideals syzygetic. This leads to a characterization of these rings in terms of the Andr\'e-Quillen homology.
    • Some numerical invariants of local rings 

      Álvarez Montaner, Josep (2002)
      Article
      Accés obert
      Let $R$ be a formal power series ring over a field of characteristic zero and $I\subseteq R$ be any ideal. The aim of this work is to introduce some numerical invariants of the local rings $R/I$ by using theory of ...
    • Sur L'Annulation du deuxième foncteur de (co)homologie D'André-Quillen 

      Planas Vilanova, Francesc d'Assís (1995)
      Article
      Accés obert
      For a given ideal I of a commutative ring ç A,B = A/I, the vanishing of the second André-Quillen (co)homology functor H2(A,B,*) is characterized in terms of the canonical homomorphism a:S(I)->R(I) from the symmetric algebra ...
    • Vanishing of the André-Quillen homology Module<math>H<sub>2</sub>(A,B,G (I))</math> 

      Planas Vilanova, Francesc d'Assís (1996)
      Article
      Accés obert
      Let $I$ be an ideal of a commutative Noetherian ring $A$, $A\supset \Q$, $B=A/I$ and ${\bf G}(I)$ the associated graded ring to $I$. It is known that $H_{2}(A,B,B)=0$ is equivalent to $I$ being syzygetic. We prove that the ...