Hierarchical matrices provide a data-sparse way to approximate fully populated matrices. In this paper we exploit H-matrix techniques to approximate the LU -decompositions of stiffness matrices as they appear in (finite element or finite difference) discretizations of convectiondominated elliptic partial differential equations. These sparse H-matrix approximations may then be used as preconditi...

we introduce a new smooth, non-toxic, biocompatible method for cross-linking of gum tragacanth (gt), a polysaccharide of natural origin, in order to serve as a new supporting matrix for immobilization systems.  the modified gum is used as a matrix for the catalysis of the conversion of benzyl penicillin to 6-aminopenicillanic acid (6-apa) by means of escherichia coli atcc11105 with penicillin g...

on L(R ) (and its half-line problem, H+, on L2(0,∞) with u(0) = 0 boundary conditions). We will focus on a new approach to the absolutely continuous spectrum σac(h) and, more generally, Σac(h), the essential support of the a.c. part of the spectral measures. What is new in our approach is that it relies on estimates on the transfer matrix, that is, the 2× 2 matrix TE(n,m) which takes (u(m+1) u(...

The most important property of the class of H-matrices, in the sense of applications presented here, is the following: every H-matrix can be diagonally scaled into a strictly diagonally dominant form. When the scaling matrix is chosen to be a diagonal matrix of the special form, we are able to characterize the corresponding subclass of H-matrices by relatively simple conditions. Precisely this ...

Let G be a finite group and C(G) be the family of representative conjugacy classes of‎ ‎subgroups of G‎. ‎The matrix whose H,K-entry is the number of ‎fixed points of the set G/K under the action of H is called the‎ ‎table of marks of G where H,K run through all elements in‎ C(G)‎. Shinsaku Fujita for the first time introduced the term “markaracter” to discuss marks for permutation representati...

Using a cohomological characterization of the consistent and the covariant Lorentz and gauge anomalies, derived from the complexification of the relevant algebras, we study in d = 2 the definition of the Weyl determinant for a non-abelian theory with Riemannian background. We obtain two second order operators that produce, by means of ζ-function regularization, respectively the consistent and t...

model order reduction is known as the problem of minimizing the -norm of the difference between the transfer function of the original system and the reduced one. in many papers, linear matrix inequality (lmi) approach is utilized to address the minimization problem. this paper deals with defining an extra matrix inequality constraint to guarantee that the minimum phase characteristic of the sys...

The role of integrable systems in string theory is discussed. We remind old examples of the correspondence between stringy partition functions or effective actions and integrable equations, based on effective application of the matrix model technique. Then we turn to a new example, coming from the Nekrasov deformation of the Seiberg-Witten prepotential. In the last case the deformed theory is d...

We consider systems (M,ω, g) withM a closed smooth manifold, ω a real valued closed one form and g a Riemannian metric, so that (ω, g) is a Morse-Smale pair, Definition 2. We introduce a numerical invariant ρ(ω, g) ∈ [0,∞] and using the theory of Dirichlet series and extensions of Witten-Helffer-Sjöstrand results improve Morse-Novikov theory for (M,ω, g) provided ρ(ω, g) < ∞. For example we sho...