By simply transforming the quadratic matrix equation into an equivalent fixed-point equation, we construct a successive approximation method and a Newton’s method based on this fixed-point equation. Under suitable conditions, we prove the local convergence of these two methods, as well as the linear convergence speed of the successive approximation method and the quadratic convergence speed of ...

The problem of giving a spectral factorization of a class of matrices arising in Wiener filtering theory and network synthesis is tackled via an kgebralc procedure. A quadratic matrix quation involving only constant matrices is shown to possess solutions which directly define a solution to the spectral factorization problem. A spectral factor with a stable inverse is defined by that unique solu...

We study the quadratic matrix equation X2 − EX − F = 0, where E is diagonal and F is an M -matrix. Quadratic matrix equations of this type arise in noisy Wiener–Hopf problems for Markov chains. The solution of practical interest is a particular M -matrix solution. The existence and uniqueness of M -matrix solutions and numerical methods for finding the desired M -matrix solution are discussed b...

We consider a special instance of the algebraic Riccati equation XCX − XE − AX + B = 0 encountered in transport theory, where the n × n matrix coefficients A,B, C, E are rank structured matrices. The equation is reduced to unilateral form A1X + A0X + A−1 = 0 and solved by means of Cyclic Reduction (CR). It is shown that the matrices generated by CR are Cauchy-like with respect to a suitable sin...

In this brief note,  using the technique of measures of noncompactness, we give some extensions of Darbo fixed point theorem. Also we prove  an existence result for a quadratic  integral equation of Hammerstein type on an unbounded interval in two variables  which includes several classes of nonlinear integral equations of Hammerstein type. Furthermore, an example is presented to show the effic...

This paper considers quadratic approximation as a narrowing tool in an interval branch-and-prune method. We seek the roots of such an approximate equation – a quadratic equation with interval parameters. Heuristics to decide, when to use the developed operator, are proposed. Numerical results for some benchmark problems are presented and analyzed.