Thomas Laffey (1997)
Banach Center Publications
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Let σ=(λ1,...,λn) be the spectrum of a nonnegative real n × n matrix. It is shown that σ is the spectrum of a nonnegative real n × n matrix having at most nonzero entries.
Gerard Sierksma, Evert Jan Bakker (1986)
Compositio Mathematica
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Jiří Rohn (1990)
Aplikace matematiky
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New proofs of two previously published theorems relating nonsingularity of interval matrices to -matrices are given.
Changjiang Bu, Wenzhe Wang, Jiang Zhou, Lizhu Sun (2014)
Czechoslovak Mathematical Journal
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The sign pattern of a real matrix , denoted by , is the -matrix obtained from by replacing each entry by its sign. Let denote the set of all real matrices such that . For a square real matrix , the Drazin inverse of is the unique real matrix such that , and , where is the Drazin index of . We say that has signed Drazin inverse if for any , where denotes the Drazin inverse of . In this paper, we give necessary conditions for some block triangular matrices...
Qing Wen Wang, Chang Lan Yang (1998)
Commentationes Mathematicae Universitatis Carolinae
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An complex matrix is called Re-nonnegative definite (Re-nnd) if the real part of is nonnegative for every complex -vector . In this paper criteria for a partitioned matrix to be Re-nnd are given. A necessary and sufficient condition for the existence of and an expression for the Re-nnd solutions of the matrix equation are presented.
Thomas Ernst (2015)
Special Matrices
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In this second article on q-Pascal matrices, we show how the previous factorizations by the summation matrices and the so-called q-unit matrices extend in a natural way to produce q-analogues of Pascal matrices of two variables by Z. Zhang and M. Liu as follows [...] We also find two different matrix products for [...]
M. Rajesh Kannan, K.C. Sivakumar (2014)
Discussiones Mathematicae - General Algebra and Applications
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Let A and B be M-matrices satisfying A ≤ B and J = [A,B] be the set of all matrices C such that A ≤ C ≤ B, where the order is component wise. It is rather well known that if A is an M-matrix and B is an invertible M-matrix and A ≤ B, then aA + bB is an invertible M-matrix for all a,b > 0. In this article, we present an elementary proof of a stronger version of this result and study corresponding results for certain other classes as well.