In this paper, we investigate the existence of a positive solution of fully fuzzy linear equation systems. This paper mainly to discuss a new decomposition of a nonsingular fuzzy matrix, the symmetric times triangular (ST) decomposition. By this decomposition, every nonsingular fuzzy matrix can be represented as a product of a fuzzy symmetric matrix S and a fuzzy triangular matrix T.

Derived decompositions of abelian categories are introduced in internal terms subcategories to construct semi-orthogonal (or Bousfield localizations, or hereditary torsion pairs) various derived categories. We give a sufficient condition for arbitrary have such and show that it is also necessary with enough projectives injectives. For bounded categories, we describe which determined by decompos...

We investigate nonsingular hypercubes, and prove several results, stating a condition for a hypercube to be the product of hypercubes of smaller dimensions. There is a shortage of higher dimensional nonsingular hypercubes in the literature. However, we show that the product of two nonsingular hypercubes is always nonsingular. Then we show how to construct four-dimensional nonsingular hypercubes...

An n × n complex matrix is full ray-nonsingular if it has no zero entries and every matrix obtained by changing the magnitudes of its entries is nonsingular. It is shown that a 5×5 full ray-nonsingular matrix does not exist. This, combined with earlier results, shows that there exists an n× n full ray-nonsingular matrix if and only if n ≤ 4.

We prove new height inequalities for determinantal ideals in a regular local ring, or more generally in a local ring of given embedding codimension. Our theorems extend and sharpen results of Faltings and Bruns. Introduction. Let φ be a map of vector bundles on a variety X. A wellknown theorem of Eagon and Northcott [EN] gives an upper bound for the codimension of the locus where φ has rank ≤ s...

Redu tions to polynomial matrix multipli ation are given for some lassi al problems involving a nonsingular input matrix over the ring of univariate polynomials with oeÆ ients from a eld. High-order lifting is used to ompute the determinant, the Smith form, and a rational system solution with about the same number of eld operations as required to multiply together two matri es having the same d...

The operational Chow cohomology classes of a complete toric variety are identified with certain functions, called Minkowski weights, on the corresponding fan. The natural product of Chow cohomology classes makes the Minkowski weights into a commutative ring; the product is computed by a displacement in the lattice, which corresponds to a deformation in the toric variety. We show that, with rati...

In this paper we study division algebras over the function fields of curves over Qp. The first and main tool is to view these fields as function fields over nonsingular S which are projective of relative dimension 1 over the p adic ring Zp. A previous paper showed such division algebras had index bounded by n assuming the exponent was n and n was prime to p. In this paper we consider algebras o...

Localisation is an important technique in ring theory and yields the construction of various rings of quotients. Colocalisation in comodule categories has been investigated by some authors (see Jara et al., Commun. Algebra, 34(8):2843– 2856, 2006 and Nastasescu and Torrecillas, J. Algebra, 185:203–220, 1994). Here we look at possible coalgebra covers π : D → C that could play the rôle of a coal...