© 2004 by London Mathematical Society
© The London Mathematical Society
Depth of Higher Associated Graded Rings
Departament d'Àlgebra i Geometria, Facultat de Matemàtiques, Universitat de Barcelona Gran Via 585, 08007 Barcelona, Spain, elias{at}mat.ub.es
Received 19 May 2003.
The depth of the associated graded ring of the powers of an ideal I of a local ring R is studied. It is proved that the depth of the associated graded ring of In is asymptotically constant when n tends to infinity, and this value is characterized in terms of ValabregaValla conditions of Im for some large integer m
0. As a corollary, a generalization is obtained of the 2-dimensional algebraic version of the GrauertRiemenschneider vanishing theorem (due to Huckaba and Huneke) to ideals satisfying the second ValabregaValla condition. The positiveness of Hilbert coefficients is also studied, and ValabregaValla conditions are linked to the vanishing of the cohomology groups of the closed fiber of the blowing up of Spec(R) along the closed sub-scheme defined by I.