1. Abstract. This article presents a fast dense solver for hierarchically off-diagonal low-rank (HODLR) matrices. This solver uses algebraic techniques such as the adaptive cross approximation (ACA) algorithm to construct the low-rank approximation of the off-diagonal matrix blocks. This allows us to apply the solver to any dense matrix that has an off-diagonal low-rank structure without any pr...

Discretizing an integral operator by a standard finite element or boundary element method typically leads to a dense matrix. Since its storage complexity grows quadratically with the number of degrees of freedom, the standard representation of the matrix as a two-dimensional array cannot be applied to large problem sizes. H2-matrix techniques use a multilevel approach to represent the dense mat...

Based on electron microscopic observations, the reproductive cycle of a relatively stable L-phase variant of Streptococcus faecalis was proposed. The small, dense, nonvesiculated L-form is envisioned as the central (core) element. It was seen to divide and bud rapidly. In addition, the dense forms appeared to be capable of growth and development within vesicles of mature mother forms. When thes...

A polarization-selective holographic optical element with compact dimensions of 2.4mm X 1mm X 1mm (width X length X thickness) is proposed. The element includes three modules: a holographic polarizing beam-splitter, a holographic input coupler, and a dove-prism coupler so that a simple and dense optical pick-up head can be achieved. Polarization properties of holographic volume gratings are bri...

The Boundary Element Tearing and Interconnecting (BETI) methods have recently been introduced as boundary element counterparts of the well–established Finite Element Tearing and Interconnecting (FETI) methods. In this paper we present inexact data–sparse versions of the BETI methods which avoid the elimination of the primal unknowns and dense matrices. However, instead of symmetric and positive...

We compare Aut(Q), the classical automorphism group of a countable dense linear order, with Autc(Q), the group of all computable automorphisms of such an order. They have a number of similarities, including the facts that every element of each group is a commutator and each group has exactly three nontrivial normal subgroups. However, the standard proofs of these facts in Aut(Q) do not work for...

The Boundary Element Tearing and Interconnecting (BETI) methods have recently been introduced as boundary element counterparts of the well–established Finite Element Tearing and Interconnecting (FETI) methods. In this paper we present inexact data–sparse versions of the BETI methods which avoid the elimination of the primal unknowns and dense matrices. However, instead of symmetric and positive...

Phosphorus is an essential element for life on earth and is also important for modern agriculture, which is dependent on inorganic fertilizers from phosphate rock. Polyphosphate is a biological polymer of phosphate residues, which is accumulated in organisms during the biological wastewater treatment process to enhance biological phosphorus removal. Here, we investigated the relationship betwee...

In this paper, we study dense subsets of boundaries of CAT(0) groups. Suppose that a group G acts geometrically on a CAT(0) space X and suppose that there exists an element g0 ∈ G such that (1) Zg0 is finite, (2) X \ Fg0 is not connnected, and (3) each component of X \ Fg0 is convex and not g0-invariant, where Zg0 is the centralizer of g0 and Fg0 is the fixed-point set of g0 in X (that is, Zg0 ...

background: serological assay based on dense granular (gra) proteins of toxoplasma gondii (t. gondii) is actually the most popular laboratory diagnostic tool to detection of toxoplasmosis. we aimed to construct a recombinant gra7-ptz57rt plasmid vectors that it is suitable for sub-cloning and gra7 protein production. m aterials and methods: souris mice were used for maintaining of t. gondii tac...