Inverse eigenvalue problems appear in a wide variety of areas in the pure and applied mathematics. They have to do with the construction of a certain matrix from some spectral information. "ssociated with any inverse eigenvalue problem, there are two important issues the existence of a solution and the construction of a solution matrix. The purpose of this chapter is to study the nonneμative inverse elementary divisors problem hereafter, NIEDP and its state of the art. The elementary divisors of a given matrix A are the characteristic polynomials of the Jordan blocks of the Jordan canonical form of A. The NIEDP looks for necessary and sufficient conditions for the existence of a nonnegative matrix with prescribed elementary divisors. Most of the content of this chapter is based on recent results published by the author and collaborators from the Mathematics Department at Universidad Católica del Norte, Chile.Keywords: nonnegative matrices, elementary divisors, Jordan canonical form, nonnegative inverse eigenvalue problems, nonnegative inverse elementary divisors problems
. IntroductionInverse problems appear in a wide variety of disciplines and they may be of many different kinds. Inverse eigenvalue problems, for instance, constitute an important subclass of inverse problems that arise in the context of mathematical modeling and parameter identification. " simple application of such problems is the construction of Leontief models in economics. Inverse eigenvalue problems have to do with constructing a certain matrix from some spectral information. "ssociated with any inverse eigenvalue problem, there are two important issues the existence of a solution and the construction of a solution matrix. The structure of the solution matrix usually it is not unique plays a fundamental role in the study of the inverse © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. eigenvalue problems. It is necessary to properly formulate the problem, otherwise it could become a trivial one. Chu and Golub [ ] say that an inverse eigenvalue problem should always be a structured problem. In this chapter, we study the Nonneμative Inverse Elementary Divisors Problem hereafter, the NIEDP , which is the problem of finding necessary and sufficient conditions for the existence of a nonnegative matrix with prescribed elementary divisors.Let A be an n × n complex matrix, and let ( ) In order that the problem be meaningful, the matrix A is required to have a particular structure. When A is required to be an entrywise nonnegative matrix, the problem is called the nonneμative inverse elementary divisors problem NIEDP see [ -] . The NIEDP is strongly related to another inverse problem, the nonneμative inverse eiμenvalue problem hereafter, the NIEP , which is the problem of determining necessary and ...