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Showing papers in "Linear Algebra and its Applications in 1974"


Journal ArticleDOI
TL;DR: In this paper, the Schur complement can be used in numerical linear algebra (NLAs) and the author is concerned with some of the ways in which it can be applied.

325 citations


Journal ArticleDOI
Miroslav Fiedler1
TL;DR: In this paper, necessary and sufficient conditions for n real numbers to be eigenvalues of an n × n nonnegative (or alternatively, positive) symmetric matrix and 2n real numbers for being eigen values and diagonal entries of a nonnegative symmetric matrices were given.

162 citations



Journal ArticleDOI
TL;DR: In this paper, the spectral inverse of a Toeplitz matrix A whose form is related to that of a circulant matrix is studied by describing the algebraic structure of the semigroup of all matrices commuting with a given matrix with distinct eigenvalues.

109 citations


Journal ArticleDOI
TL;DR: In this paper, the rank of the controllability matrix of A and W is used to derive a new inertia theorem for damping problems of the equation M x + (D + G) xdot; + Kx = 0.

99 citations


Journal ArticleDOI
TL;DR: The definition of a projector under a semileast square inverse of a complex matrix is given in this article, where the same concept can also be defined in terms of projectors under seminorms.

63 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the range of Φ is exactly the set of all invertible operators T for which T−1 is similar to T∗.

58 citations


Journal ArticleDOI
TL;DR: In this paper, an iterative method is described which rapidly computes the norm of a nonnegative matrix A, considered as a mapping from the finite dimensional space l r(n) to the space l p(m).

42 citations


Journal ArticleDOI
TL;DR: This paper showed that the Moore-Penrose inverse of AB can always be expressed as B−A− for some generalized inverse A− of A and B− of B. Some of the proofs are based on conditions for a product of projectors to be a projector.

39 citations


Journal ArticleDOI
TL;DR: Schneider-Vidyasagar et al. as discussed by the authors showed that the connections between A quasimonotone and exp( tA ) monotone are special cases of differential inequalities for initial value problems in partially ordered topological vector spaces.

36 citations


Journal ArticleDOI
TL;DR: In this paper, the authors characterized all n x n matrices whose spectral radius equals their spectral norm and showed that for n ⩾3 the class of these matrices contains the normal matrices as a subclass.

Journal ArticleDOI
TL;DR: In this paper, a new lower bound for the Perron root ω of an irreducible nonnegative matrix A is obtained, where ω is greater than the sum of the greatest element of A plus the arithmetic mean of the two smallest main diagonal elements.

Journal ArticleDOI
TL;DR: A brief survey of recent results on combinatorially symmetric matrices can be found in this paper, where a simple proof of a theorem of Parker and Youngs is presented.

Journal ArticleDOI
TL;DR: For the eigenvalues λi of an n × n matrix A the inequality ∑ i |λ i | 2 (A 4 − 1 2 ‖D 2 ) 1 2 is proved, where D ≔ AA ∗ − A ∗ A and ‖ ● ‖; denotes the euclidean norm.

Journal ArticleDOI
TL;DR: Some theorems concerning the application of the e-algorithm to vectors satisfying a matrix difference equation are proved and generalize results on the scalar e-Algorithm and some recent theorem on the vector e- algorithm.

Journal ArticleDOI
TL;DR: A Lyapunov transformation is a linear transformation on the set H n of hermitian matrices H ϵ C n,n of the form L A(H) = A∗H + HA, where H is positive definite as mentioned in this paper.

Journal ArticleDOI
TL;DR: For a square complex matrix A with positive definite imaginary component (A − A ∗ )⧸ 2 i, this paper studied Hermitian congruence, distribution of the eigenvalues {αj} of A − 1 A − ∗ relative to a line in the complex plane, variational properties of the arguments, real parts and imaginary parts of {aj}, and inequalities for determinants and singular values.

Journal ArticleDOI
TL;DR: In this paper, some results were obtained relating topological properties of polyhedral cones to algebraic properties of matrices whose columns are the extremal vectors of the cone. And several characterizations of positive operators on polyhedral cone are given.

Journal ArticleDOI
TL;DR: In this paper, the determinantal values for submatrices of two-commodity transportation problems (in terms of the number of disjoint capacitated routes) were established.

Journal ArticleDOI
TL;DR: It is shown that if a linear transformation T on the space of n × n complex matrices maps non negative matrices into nonnegative matrices and preserves the spectrum of each nonnegative matrix, then T ( A) = P −1 AP or T (A) = T −1 A T P for all matrices A and a fixed nonnegative generalized permutation matrix P.

Journal ArticleDOI
TL;DR: In this article, it was shown that a bounded multiplicative group of complex (real) n × n nonsingular matrices is similar to a unitary (orthogonal) group.


Journal ArticleDOI
TL;DR: A necessary and sufficient condition for the existence of unitary matrices U and V such that UAV is a real diagonal matrix for every matrix A in some set Γ of rectangular complex matrices is given in this article.


Journal ArticleDOI
TL;DR: In this article, it was shown that if S is a family of n×n normal matrices, and As is the algebra generated by S over the complex field, then the matrices in S are simultaneously unitarily similar to quasi-diagonal matrices if and only if (AB − BA)2Q = Q(AB −BA)2 for all A and B ∈ As, Q ∈ S. In fact, the domain of B can be further restricted.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the numerical properties of the maximum and minimum diagonal sums of the matrices in the convex polyhedron of all n × n doubly stochastic (d.s.) matrices.

Journal ArticleDOI
TL;DR: In this article, the spectral properties of an integral operator with a nonnegative continous kernel are investigated. But the authors focus on the spectral radius of the integral operator and do not consider the distribution of secondary eigenvalues.

Journal ArticleDOI
TL;DR: In this paper, some new theorems are presented on the isolation effect in Hermitian matrices and the results are of importance in the computation of eigenvalues, particularly for tridiagonal matrices.

Journal ArticleDOI
TL;DR: In this article, the authors present conditions which are necessary and sufficient for (AB >) + = B + A ω for all normalized generalized inverses of the complex matrix A.

Journal ArticleDOI
TL;DR: In this article, nonnegative matrices which are equal to their Moore-Penrose generalized inverse are characterized, where the inverse is defined as the inverse of the original matrices.