scholarly journals Pseudo Schur complements, pseudo principal pivot transforms and their inheritance properties

2015 ◽  
Vol 30 ◽  
Author(s):  
K. Sivakumar ◽  
Ravindran G. ◽  
Kavita Bisht

Extensions of the Schur complement and the principal pivot transform, where the usual inverses are replaced by the Moore-Penrose inverse, are revisited. These are called the pseudo Schur complement and the pseudo principal pivot transform, respectively. First, a generalization of the characterization of a block matrix to be an M-matrix is extended to the nonnegativity of the Moore-Penrose inverse. A comprehensive treatment of the fundamental properties of the extended notion of the principal pivot transform is presented. Inheritance properties with respect to certain matrix classes are derived, thereby generalizing some of the existing results. Finally, a thorough discussion on the preservation of left eigenspaces by the pseudo principal pivot transformation is presented.

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zdeněk Dostál ◽  
Tomáš Brzobohatý ◽  
Oldřich Vlach

Abstract Bounds on the spectrum of Schur complements of subdomain stiffness matrices with respect to the interior variables are key ingredients of the convergence analysis of FETI (finite element tearing and interconnecting) based domain decomposition methods. Here we give bounds on the regular condition number of Schur complements of “floating” clusters arising from the discretization of 3D Laplacian on a cube decomposed into cube subdomains. The results show that the condition number of the cluster defined on a fixed domain decomposed into m × m × m cube subdomains connected by face and optionally edge averages increases proportionally to m. The estimates support scalability of unpreconditioned H-FETI-DP (hybrid FETI dual-primal) method. Though the research is most important for the solution of variational inequalities, the results of numerical experiments indicate that unpreconditioned H-FETI-DP with large clusters can be useful also for the solution of huge linear problems.


2008 ◽  
Vol 54 ◽  
pp. 70-81 ◽  
Author(s):  
Mohsen Shahinpoor

This article covers advances made in connection with Ionic Polymeric-Conductor Nano Composites (IPCNCs) as distributed biomimetic nanosensors, nanoactuators, nanorobots and artificial muscles. A review of the fundamental properties and characteristics of IPCNCs will first be presented. This summary will include descriptions of the basic materials' molecular structure and subsequent procedure to manufacture the basic material for chemical plating and electroactivation. Further described are chemical molecular plating technologies to make IPCNCs, nanotechnologies of manufacturing and trapping of nanoparticles, SEM, TEM, SPM and AFM characterization of IPMNCs, biomimetic sensing and actuation characterization techniques, electrical characterization and equivalent circuit modeling of IPCNCs as electronic materials. A phenomenological model of the underlying sensing and actuation mechanisms is also presented based on linear irreversible thermodynamics with two driving forces, an electric field and a solvent pressure gradient and two fluxes, electric current density and the ionic+solvent flux. The presentation concludes with a number of videos and some live demos.


2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Orhan Tug

We firstly summarize the related literature about Br,s,t,u-summability of double sequence spaces and almost Br,s,t,u-summable double sequence spaces. Then we characterize some new matrix classes of Ls′:Cf, BLs′:Cf, and Ls′:BCf of four-dimensional matrices in both cases of 0<s′≤1 and 1<s′<∞, and we complete this work with some significant results.


1992 ◽  
Vol 282 ◽  
Author(s):  
H. Treichel ◽  
A. Mitwalsky ◽  
G. Tempel ◽  
G. Zorn ◽  
W. Kern ◽  
...  

ABSTRACTFilms of tantalum pentoxide (Ta2O5) have been fabricated by use of different precursor materials, deposition techniques and annealing procedures. Several analytical methods were appliedto study the layers. Fundamental properties and new data are reportedand related to practical features that are of importance in device design and manufacturing of advanced, highly integrated devices. This overview may facilitate the choice of an optimal combination of precursor, deposition technique and corresponding annealing procedure for aspecific application of these films in microelectronics, since the electrical properties reveal the potential of Ta2O5 films for the use in 64Mbit and 256Mbit DRAM devices as high dielectric constant material.


1971 ◽  
Vol 3 (3) ◽  
pp. 283-305 ◽  
Author(s):  
C A Gannon

Spatial demand is the aggregate demand expressed at a particular location, under given supply conditions, by a set of individual consumers whose locations are dispersed over a geographical market area. Although the concept of spatial demand has played a central role in location and spatial economics since its development by Lösch and his incorporation of it into his model of spatial competitive equilibrium, a comprehensive rigorous characterization of spatial demand does not presently exist. Accordingly, the contribution of this paper is a quite general formulation of spatial demand and a rigorous specification and evaluation of some of its most important properties. Spatial demand is found to consist of two components: free spatial demand which corresponds to a situation in which the geographic market areas of suppliers do not interact, and competitive spatial demand which corresponds to a situation in which they do. This distinction allows the derivation of conditions for, among other things, the (1) existence of these two components, (2) continuity of the spatial demand function and its first derivative, and (3) convexity or concavity of the spatial demand function. Such properties of spatial demand are basic to an evaluation of the existence, stability, and general nature of spatial competitive equilibrium.


2005 ◽  
Vol 37 (3) ◽  
pp. 801-818
Author(s):  
Richard F. Serfozo

In this study, we characterize the equilibrium behavior of spatial migration processes that represent population migrations, or birth-death processes, in general spaces. These processes are reversible Markov jump processes on measure spaces. As a precursor, we present fundamental properties of reversible Markov jump processes on general spaces. A major result is a canonical formula for the stationary distribution of a reversible process. This involves the characterization of two-way communication in transitions, using certain Radon-Nikodým derivatives. Other results concern a Kolmogorov criterion for reversibility, time reversibility, and several methods of constructing or identifying reversible processes.


Gene ◽  
2015 ◽  
Vol 571 (1) ◽  
pp. 117-125 ◽  
Author(s):  
Yujiro Hattori ◽  
Hirotaka Ishii ◽  
Akio Morita ◽  
Yasuo Sakuma ◽  
Hitoshi Ozawa

Author(s):  
Fabian Freyenhagen

Critical Theory is an umbrella term to denote those theorists who take up the task described by Karl Marx as the self-clarification of the age struggles and wishes of the age. As such, two elements are crucial: (a) a connection to social and political struggles of emancipation, and (b) self-reflexivity. Critical Theorists differ—sometimes quite fundamentally—about what these two elements require (and how they relate). For example, some such theorists (such as Max Horkheimer or Michel Foucault) take the normative orientations of struggles for emancipation as something that does not require grounding at the level of theorizing, while others (such as Jürgen Habermas) think such grounding is the main task of Critical Theory, securing moral validity for the struggles. These substantive differences also mean that there are no accepted methods on which all Critical Theorists would agree. To stay with the example, those Critical Theorists who reject discursive grounding of its normative standards tend to engage in genealogy and other disclosing forms of social critique; while those who seek discursive grounding employ reconstructive and/or constructivist methods. The existence of fundamental substantive and methodological differences among proponents of Critical Theory means that it is difficult, or perhaps even impossible, to give a uniform characterization of it. Sometimes, Critical Theory is defined institutionally. Then it is denoting a succession of theorists (often classed into different generations) who are connected to the Institute of Social Research and/or the Philosophy Department in Frankfurt am Main, Germany—the so-called “Frankfurt School.” However, this institutional definition has only limited use. The disagreements among thinkers within the Frankfurt School tradition can run deep—sometimes deeper than they run with theorists, like Foucault, who are not connected institutionally to it. And it is an open and contested question whether everyone institutionally connected to the Frankfurt School is engaged in Critical Theory. Thinking systematically about the task of self-reflexively connecting to struggles of emancipation requires a different approach. It is helpful to understand Critical Theory as a broad and varied tradition, with core cases (such as Horkheimer’s 1937 text “Traditional and Critical Theory”), but no sharp boundaries. Understood that way, there cannot be a fully comprehensive treatment of Critical Theory, but it is possible to think of this tradition as involving multiple morphing sequences, whereby approaches are amended in various ways over time and thereby change into something else. One important dividing line is how historical or transcendental one takes Marx’s task to be—some proponents of Critical Theory are, in effect, historical contextualists, while others seek to establish the conditions of possibility of human interaction as such.


Filomat ◽  
2017 ◽  
Vol 31 (19) ◽  
pp. 6101-6112 ◽  
Author(s):  
Hemen Dutta ◽  
Jyotishmaan Gogoi

In 1996, M. Stojakovic and Z. Stojakovic examined the convergence of a sequence of fuzzy numbers via Zadeh?s Extension Principle, which is quite difficult for practical use. In this paper, we utilize the notion ?-level sets to deal with convergence and summable related notions and adopted a relatively new approach to characterize matrix classes involving some sets of single sequences of fuzzy numbers. The approach is expected to be useful in dealing with characterization of several other matrix classes involving different kinds of sets of sequences of fuzzy numbers, single or multiple


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