Browsing by Author "Álvarez Montaner, Josep"
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A Koszul complex over skew polynomial rings
Álvarez Montaner, Josep; Boix, Alberto F.; Zarzuela Armengou, Santiago (20190101)
Article
Open AccessWe construct a Koszul complex in the category of left skew polynomial rings associated with a flat endomorphism that provides a finite free resolution of an ideal generated by a Koszul regular sequence 
A surprising fact about Dmodules in characteristic p>0
Álvarez Montaner, Josep; Planas Vilanova, Francesc d'Assís (2004)
External research report
Open AccessLet R = k[x1, . . . , xd] be the polynomial ring in d independent variables, where k is a field of characteristic p > 0. Let DR be the ring of klinear differential operators of R and let f be a polynomial in R. In this ... 
Addendum to "Frobenius and Cartier algebras of StanleyReisner rings" [J.Algebra 358 (2012), 162177]
Álvarez Montaner, Josep; Yanagawa, Kohji (201305)
External research report
Open AccessWe give a purely combinatorial characterization of complete StanleyReisner rings having a principally generated (equivalently, nitely generated) Cartier algebra 
Addendum to “Frobenius and Cartier algebras of Stanley–Reisner rings” [J. Algebra 358 (2012) 162–177]
Álvarez Montaner, Josep; Yanagawa, Kohji (201409)
Article
Restricted access  publisher's policyWe give a purely combinatorial characterization of complete Stanley–Reisner rings having a principally generated (equivalently, finitely generated) Cartier algebra. 
Bass numbers of local cohomology of cover ideals of graphs
Álvarez Montaner, Josep; Sohrabi, Fatemeh (2020)
Article
Open AccessWe 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 ... 
Bass numbers of local cohomology of cover ideals of graphs
Álvarez Montaner, Josep; Sohrabi, Fatemeh (2019)
External research report
Open AccessWe develop splitting techniques to study 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 are ... 
Bernstein's inequality and holonomicity for certain singular rings
Álvarez Montaner, Josep; Jeffries, Jack; NúñezBetancourt, Luis; Hernández, Daniel J.; Teixeira, Pedro; Witt, Emily E. (2021)
External research report
Open AccessIn this manuscript we prove the Bernstein inequality and develop the theory of holonomic Dmodules for rings of invariants of finite groups in characteristic zero, and for strongly Fregular finitely generated graded ... 
BernsteinSato functional equations, Vfiltrations, and multiplier ideals of direct summands
Álvarez Montaner, Josep; Jeffries, Jack; NúñezBetancourt, Luis (2019)
External research report
Open AccessThis paper investigates the existence and properties of a Bernstein– Sato functional equation in nonregular settings. In particular, we construct Dmodules in which such formal equations can be studied. The existence of ... 
Characteristic cycle of local cohomology modules of monomial ideals II
Álvarez Montaner, Josep (2003)
Article
Open Access 
Characteristic cycles of local cohomology modules of monomial ideals
Álvarez Montaner, Josep (1998)
Article
Open AccessBy using the theory of Dmodules 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
Open AccessFor 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 ... 
Cohomología local con soporte un ideal monomial (Dmódulos y combinatoria)
Álvarez Montaner, Josep (2000)
Article
Open AccessWe study, by using the theory of algebraic $\cD$modules, the local cohomology modules supported on a monomial ideal $I$ of the polynomial ring $R=k[x_1,\dots,x_n]$, where $k$ is a field of characteristic zero. We compute ... 
Cohomología local con soporte un ideal monomial (Dmódulos y combinatoria)
Álvarez Montaner, Josep (Edicions UPC, 2000)
Conference report
Restricted access  publisher's policyWe study, by using the theory of algebraic Dmodules, the local cohomology modules supported on a monomial ideal I of the polynomial ring R = k[x1, . . . , xn], where k is a field of characteristic zero. We compute the ... 
Computing jumping numbers and multiplier ideals in twodimensional regular local rings
Alberich Carramiñana, Maria; Álvarez Montaner, Josep; Dachs Cadefau, Ferran (Universitat de Barcelona. Edicions i Publicacions, 2014)
Conference report
Restricted access  publisher's policyWe give a new algorithm that computes the jumping numbers with their multiplicities and multiplier ideals of any ideal in a regular twodimensional local ring. 
Constancy regions of mixed multiplier ideals in twodimensional local rings with rational singularities
Alberich Carramiñana, Maria; Álvarez Montaner, Josep; Dachs Cadefau, Ferran (WILEYVCH Verlag GmbH & Co. KGaA, Weinheim, 2018)
Article
Open AccessThe aim of this paper is to study mixed multiplier ideals associated with a tuple of ideals in a twodimensional local ring with a rational singularity. We are interested in the partition of the real positive orthant given ... 
Dmodules, BernsteinSato polynomials and Finvariants of direct summands
Álvarez Montaner, Josep; Huneke, Craig; NúñezBetancourt, Luis (20171201)
Article
Open AccessWe study the structure of D modules over a ring R which is a direct sum mand of a polynomial or a power series ring S with coefficients over a field. We relate properties of D modules over R to D modules over S . We ... 
Divisors of expected Jacobian type
Álvarez Montaner, Josep; Planas Vilanova, Francesc d'Assís (2020)
External research report
Open AccessDivisors whose Jacobian ideal is of linear type have received a lot of attention recently because of its connections with the theory of Dmodules. In this work we are interested on divisors of expected Jacobian type, that ... 
Effective computation of base points of ideals in twodimensional local rings
Alberich Carramiñana, Maria; Álvarez Montaner, Josep; Blanco Fernández, Guillem (20180104)
Article
Open Access© 2018 Elsevier Ltd. We provide an algorithm that allows to describe the minimal logresolution of an ideal in a smooth complex surface from the minimal logresolution of its generators. In order to make this algorithm ... 
Frobenius and Cartier algebras of StanleyReisner rings
Álvarez Montaner, Josep; Boix, Alberto F.; Zarzuela Armengou, Santiago (201109)
External research report
Open AccessWe study the generation of the Frobenius algebra of the injective hull of a complete StanleyReisner ring over a field with positive characteristic. In particular, by extending the ideas used by M. Katzman to give a ... 
Frobenius and Cartier algebras of StanleyReisner rings
Álvarez Montaner, Josep; Boix, Alberto F.; Zarzuela Armengou, Santiago (20110515)
Article
Restricted access  publisher's policyWe study the generation of the Frobenius algebra of the injective hull of a complete Stanley–Reisner ring over a field with positive characteristic. In particular, by extending the ideas used by M. Katzman to give a ...