Abstract In multistage perfect matching problems, we are given a sequence of graphs on the same vertex set and asked to find matchings, corresponding graphs, such that consecutive matchings as similar possible. More precisely, aim maximize intersections, or minimize unions between matchings. We show these problems NP-hard even in very restricted scenarios. As our main contribution, present firs...

In this paper we propose a Modiied Block Newton Method for approximating an invariant subspace S and the corresponding eigenvalues of a symmetric matrix A. The method generates a sequence of matrices Z (k) which span subspaces S k approximating S. The matrices Z (k) are calculated via a Newton step applied to a special formulation of the block eigenvalue problem for the matrix A, followed by a ...

The problem of determining the points in a plane undergoing rigid body co-planar motion which deviate least from concentric circles in a given sequence of its ordered position sets is considered. The sought for approximation is the one which minimizes the sum of squared algebraic deviations (distances) of such points from the concentric circles approximating their paths in the given alternating...

As a generalization of countably C-approximating posets, the concept of countably QC-approximating posets is introduced. With the countably QC-approximating property, some characterizations of generalized completely distributive lattices and generalized countably approximating posets are given. The main results are as follows: (1) a complete lattice is generalized completely distributive if and...

On utilizing the spectral representation of selfadjoint operators in Hilbert spaces, some error bounds in approximating $n$-time differentiable functions of selfadjoint operators in Hilbert Spaces via a Taylor's type expansion are given.

Abstract The main goal of this paper is to study a class differential nonlinear system involving parabolic variational and history-dependent hemivariational inequalities in Banach spaces by using the penalty method. We first construct penalized problem for such then derive existence uniqueness its solution obtain an approximating sequence system. Moreover, we prove strong convergence obtained o...

We consider here the problem of minimizing a polynomial function on Rn. The problem is known to be hard even for degree 4. Therefore approximation algorithms are of interest. Lasserre [11] and Parrilo [16] have proposed approximating the minimum of the original problem using a hierarchy of lower bounds obtained via semidefinite programming relaxations. We propose here a method for computing a c...

An adaptive minimum symbol error rate (MSER) linear multiuser detector (MUD) is proposed for direct sequence code division multiple access (DS-CDMA) systems employing multilevel pulseamplitude modulation ( -PAM) scheme. Based on a kernel density estimation for approximating the symbol error rate (SER) from training data, a least mean squares (LMS) style stochastic gradient algorithm called the ...

We extend the study on the homogenization problem for an elastic material containing a distributed array of gas bubbles to the case when the body force depends on time. By technically constructing an approximating sequence, we are able to show the convergence of semigroups and therefore prove the main result that such spongy material can be approximated by an elastic material without holes in t...