this paper deals with scrutinizing the convergence properties of iterative methods to solve linear system of equations. recently, several types of the preconditioners have been applied for ameliorating the rate of convergence of the accelerated overrelaxation (aor) method. in this paper, we study the applicability of a general class of the preconditioned iterative methods under certain conditio...

We have obtained constraints on the strength and orientation of anisotropy in the mantle beneath the Tonga, southern Kuril, Japan, and Izu-Bonin subduction zones using shear-wave splitting in S phases from local earthquakes and in teleseismic core phases such as SKS. The observed splitting in all four subduction zones is consistent with a model in which the lower transition zone (520–660 km) an...

Requirements concerning the construction of a minimal photosynthetic design cell with direct coupling of water-splitting photosynthesis and H2 production are discussed in the present paper. Starting from a cyanobacterial model cell, Synechocystis PCC 6803, potentials and possible limitations are outlined and realization strategies are presented. In extension, the limits of efficiency of all maj...

We introduce the notion of a preindependence relation between subsets of the big model of a complete first-order theory, an abstraction of the properties which numerous concrete notions such as forking, dividing, thorn-forking, thorn-dividing, splitting or finite satisfiability share in all complete theories. We examine the relation between four additional axioms (extension, local character, fu...

Let B,C be Boolean algebras and e : B → C an embedding. We examine the hierarchy of ideals on C for which e : B → C/I is a regular (i.e. complete) embedding. As an application we deal with the interrelationship between P(ω)/fin in the ground model and in its extension. If M is an extension of V containing a new subset of ω, then in M there is an almost disjoint re nement of the family ([ω]) . M...

We introduce an extension of the Pólya tree approach for constructing distributions on the space of probability measures. By using optional stopping and optional choice of splitting variables, the construction gives rise to random measures that are absolutely continuous with piecewise smooth densities on partitions that can adapt to fit the data. The resulting “optional Pólya tree” distribution...

We present approximation algorithms and structural results for problems in network design. We give improved approximation algorithms for nding min-cost k-outconnected graphs with either a single root or multiple roots for (i) uniform costs, and (ii) metric costs. The improvements are obtained by focusing on single-root k-outconnected graphs and proving (i) a version of Mader's critical cycle th...