Weak multiplication modules
In this paper we characterize weak multiplication modules.
Weitzenböck Derivations and Classical Invariant Theory: I. Poincaré Series
2000 Mathematics Subject Classification: 13N15, 13A50, 16W25.By using classical invariant theory approach, formulas for computation of the Poincaré series of the kernel of linear locally nilpotent derivations are found.
Weitzenböck Derivations and Classical Invariant Theory II: The Symbolic Method
2000 Mathematics Subject Classification: 13N15, 13A50, 13F20.An analogue of the symbolic method of classical invariant theory for a representation and manipulation of the elements of the kernel of Weitzenböck derivations is developed.
When does the -signature exist?
We show that the -signature of an -finite local ring of characteristic exists when is either the localization of an -graded ring at its irrelevant ideal or -Gorenstein on its punctured spectrum. This extends results by Huneke, Leuschke, Yao and Singh and proves the existence of the -signature in the cases where weak -regularity is known to be equivalent to strong -regularity.
When is a Ring of Torus Invariants a Polynomial Ring?
When is the algebra of multisymmetric polynomials generated by the elementary multisymmetric polynomials?
When spectra of lattices of -ideals are Stone-Čech compactifications
Let be a completely regular Hausdorff space and, as usual, let denote the ring of real-valued continuous functions on . The lattice of -ideals of has been shown by Martínez and Zenk (2005) to be a frame. We show that the spectrum of this lattice is (homeomorphic to) precisely when is a -space. This we actually show to be true not only in spaces, but in locales as well. Recall that an ideal of a commutative ring is called a -ideal if whenever two elements have the same annihilator and...
When the Dual of an Ideal is a Ring.
Which fields have no maximal subrings ?