scholarly journals Pólya's Permanent Problem

10.37236/1832 ◽  
2004 ◽  
Vol 11 (1) ◽  
Author(s):  
William McCuaig

A square real matrix is sign-nonsingular if it is forced to be nonsingular by its pattern of zero, negative, and positive entries. We give structural characterizations of sign-nonsingular matrices, digraphs with no even length dicycles, and square nonnegative real matrices whose permanent and determinant are equal. The structural characterizations, which are topological in nature, imply polynomial algorithms.

Author(s):  
Leiba Rodman

This chapter presents canonical forms for real and complex matrices and for pairs of real and complex matrices, or matrix pencils, with symmetries. All these forms are known, and most are well-known. The chapter first looks at Jordan and Kronecker canonical forms, before turning to real matrix pencils with symmetries. It provides canonical forms for pairs of real matrices, either one of which is symmetric or skewsymmetric, or what is the same, corresponding matrix pencils. Finally, this chapter presents canonical forms of complex matrix pencils with various symmetries, such as complex matrix pencils with symmetries with respect to transposition.


2017 ◽  
Vol 32 ◽  
pp. 357-364 ◽  
Author(s):  
Rachid Marsli ◽  
Frank Hall

The research in this paper is motivated by a recent work of I. Barany and J. Solymosi [I. Barany and J. Solymosi. Gershgorin disks for multiple eigenvalues of non-negative matrices. Preprint arXiv no. 1609.07439, 2016.] about the location of eigenvalues of nonnegative matrices with geometric multiplicity higher than one. In particular, an answer to a question posed by Barany and Solymosi, about how the location of the eigenvalues can be improved in terms of their geometric multiplicities is obtained. New inclusion sets for the eigenvalues of a real square matrix, called Ger\v{s}gorin discs of the second type, are introduced. It is proved that under some conditions, an eigenvalue of a real matrix is in a Ger\v{s}gorin disc of the second type. Some relationships between the geometric multiplicities of eigenvalues and these new inclusion sets are established. Some other related results, consequences, and examples are presented. The results presented here apply not only to nonnegative matrices, but extend to all real matrices, and some of them do not depend on the geometric multiplicity.


2020 ◽  
Vol 21 (1) ◽  
pp. 24-28
Author(s):  
Badrulfalah Badrulfalah ◽  
Iis Irianingsih ◽  
Khafsah Joebaedi

This paper discusses a nonlinear boundary value problem of system with rectangular coefficients of the form  with boundary conditions of the form  A(t)x' + B(t)x = f(t,x) and  which is  is a real  matrix with  whose entries are continuous on the form B1x(to)=a  and B2x(T)=b which is A(t) is a real m  n matri with m > n matrix with m > n whose entries  are continuous on J = [to,T] and f E C[J x Rn, Rn]. B1, B2  are nonsingular matrices such that  and  are constant vectors, especially about the proof of the uniqueness of its solution. To prove it, we use Moore-Penrose generalized inverse and method of variation of parameters to find its solution. Then we show the uniqueness of it by using fixed point theorem of contraction mapping. As the result, under a certain condition, the boundary value problem has a unique  solution.


2020 ◽  
Vol 36 (36) ◽  
pp. 664-677
Author(s):  
João Ferreira Alves

The purpose of this note is to obtain rational criteria for diagonalizability of real matrices through the analysis of the moment and Gram matrices associated to a given real matrix. These concepts were introduced by Horn and Lopatin in [R.A. Horn and A.K. Lopatin. The moment and Gram matrices, distinct eigenvalues and zeroes, and rational criteria for diagonalizability. Linear Algebra and its Applications, 299:153-163, 1999] for complex matrices. However, when the matrix is real, it is possible to combine their results with the Borchardt-Jacobi Theorem, in order to get new and noteworthy rational criteria.


1980 ◽  
Vol 3 (1) ◽  
pp. 15-36
Author(s):  
Grzegorz Rozenberg ◽  
Dirk Vermeir

The concept of metalinearity in ETOL systems is investigated. Some structural characterizations, a pumping lemma and the closure properties of the resulting class of languages are established. Finally, some applications in the theory of L systems of finite index are provided.


2021 ◽  
Vol 1233 ◽  
pp. 130043
Author(s):  
Hua Zhang ◽  
Ting Xu ◽  
Dongdong Li ◽  
Tao Cheng ◽  
Jing Chen ◽  
...  

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