1,069 research outputs found
Generalized Perron--Frobenius Theorem for Nonsquare Matrices
The celebrated Perron--Frobenius (PF) theorem is stated for irreducible
nonnegative square matrices, and provides a simple characterization of their
eigenvectors and eigenvalues. The importance of this theorem stems from the
fact that eigenvalue problems on such matrices arise in many fields of science
and engineering, including dynamical systems theory, economics, statistics and
optimization. However, many real-life scenarios give rise to nonsquare
matrices. A natural question is whether the PF Theorem (along with its
applications) can be generalized to a nonsquare setting. Our paper provides a
generalization of the PF Theorem to nonsquare matrices. The extension can be
interpreted as representing client-server systems with additional degrees of
freedom, where each client may choose between multiple servers that can
cooperate in serving it (while potentially interfering with other clients).
This formulation is motivated by applications to power control in wireless
networks, economics and others, all of which extend known examples for the use
of the original PF Theorem.
We show that the option of cooperation between servers does not improve the
situation, in the sense that in the optimal solution no cooperation is needed,
and only one server needs to serve each client. Hence, the additional power of
having several potential servers per client translates into \emph{choosing} the
best single server and not into \emph{sharing} the load between the servers in
some way, as one might have expected.
The two main contributions of the paper are (i) a generalized PF Theorem that
characterizes the optimal solution for a non-convex nonsquare problem, and (ii)
an algorithm for finding the optimal solution in polynomial time
On complex power nonnegative matrices
Power nonnegative matrices are defined as complex matrices having at least
one nonnegative integer power. We exploit the possibility of deriving a Perron
Frobenius-like theory for these matrices, obtaining three main results and
drawing several consequences. We study, in particular, the relationships with
the set of matrices having eventually nonnegative powers, the inverse of M-type
matrices and the set of matrices whose columns (rows) sum up to one
Matrix Roots of Eventually Positive Matrices
Eventually positive matrices are real matrices whose powers become and remain
strictly positive. As such, eventually positive matrices are a fortiori matrix
roots of positive matrices, which motivates us to study the matrix roots of
primitive matrices. Using classical matrix function theory and Perron-Frobenius
theory, we characterize, classify, and describe in terms of the real Jordan
canonical form the th-roots of eventually positive matrices.Comment: Accepted for publication in Linear Algebra and its Application
A Perron theorem for matrices with negative entries and applications to Coxeter groups
Handelman (J. Operator Theory, 1981) proved that if the spectral radius of a
matrix is a simple root of the characteristic polynomial and is strictly
greater than the modulus of any other root, then is conjugate to a matrix
some power of which is positive. In this article, we provide an explicit
conjugate matrix , and prove that the spectral radius of is a simple and
dominant eigenvalue of if and only if is eventually positive. For
real matrices with each row-sum equal to , this criterion can be
declined into checking that each entry of some power is strictly larger than
the average of the entries of the same column minus . We apply the
criterion to elements of irreducible infinite nonaffine Coxeter groups to
provide evidences for the dominance of the spectral radius, which is still
unknown.Comment: 14 page
On the max-algebraic core of a nonnegative matrix
The max-algebraic core of a nonnegative matrix is the intersection of column
spans of all max-algebraic matrix powers. Here we investigate the action of a
matrix on its core. Being closely related to ultimate periodicity of matrix
powers, this study leads us to new modifications and geometric
characterizations of robust, orbit periodic and weakly stable matrices.Comment: 27 page
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