Resultants are defined in the sparse (or toric) context in order to exploit the structure of the polynomials as expressed by their Newton polytopes. Since determinantal formulae are not always possible, the most efficient general method for computing resultants is as the ratio of two determinants. This is made possible by Macaulay’s seminal result [15] in the dense homogeneous case, extended by...

For a Noetherian local domain A, there exists an upper bound Nτ (A) on the minimal number of generators of any height two ideal a for which A/a is Cohen-Macaulay of type τ . More precisely, we may take Nτ (A) := (τ + 1)eh(A), where eh(A) is the homological multiplicity of A.

A concrete description of all graded maximal Cohen–Macaulay modules of rank one and two over the non-isolated singularities of type y3 1 +y 2 1y3−y 2y3 is given. For this purpose we construct an alghoritm that provides extensions of MCM modules over an arbitrary hypersurface.

A balanced Cohen-Macaulay algebra is a connected algebra A having a balanced dualizing complex ωA[d] in the sense of Yekutieli (1992) for some integer d and some graded A-A bimodule ωA. We study some homological properties of a balanced Cohen-Macaulay algebra. In particular, we will prove the following theorem: Theorem 0.1. Let A be a Noetherian balanced Cohen-Macaulay algebra, and M a nonzero ...

In [11], Haiman proved the remarkable result that the isospectral Hilbert scheme of points in the plane is normal, Cohen-Macaulay and Gorenstein. He also showed that this implies the n! conjecture and the positivity conjecture for the Kostka-Macdonald coefficients. In addition, he conjectured that the isospectral Hilbert scheme over the principal component of Hilb(Cd) is Cohen-Macaulay for any ...

We develop a new approach for establishing the Macaulayness of posets representable as cartesian powers of other posets. This approach is based on a problem of constructing an ideal of maximum rank in a poset. Using the relations between the maximum rank ideal problem and the edge-isoperimetric problem on graphs we demonstrate an application of our approach to specification of all posets with a...