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Grigoris Kalogeropoulos

Publications and source records attributed to Grigoris Kalogeropoulos.

10 recordsLinked to original sources
arXiv2017

Optimal equilibrium for a reformulated Samuelson economical model

This paper studies the equilibrium of an extended case of the classical Samuelson's multiplier-accelerator model for national economy. This case has incorporated some kind of memory into the system. We assume that total consumption and private investment depend upon the national income values. Then, delayed difference equations of third order are employed to describe the model, while the respective solutions of third order polynomial, correspond to the typical observed business cycles of real economy. We focus on the case that the equilibrium is not unique and provide a method to obtain the optimal equilibrium.

math.DS↗
arXiv2017

The Samuelson's model as a singular discrete time system

In this paper we revisit the famous classical Samuelson's multiplier-accelerator model for national economy. We reform this model into a singular discrete time system and study its solutions. The advantage of this study gives a better understanding of the structure of the model and more deep and elegant results.

math.DS↗
arXiv2016

The case of a generalised linear discrete time system with infinite many solutions

In this article we study a class of generalised linear systems of difference equations with given non-consistent initial conditions and infinite many solutions. We take into consideration the case that the coefficients are square constant matrices with the leading coefficient singular. We provide optimal solutions and numerical examples to justify our theory.

math.DS↗
arXiv2016

A boundary value problem of a generalised linear discrete time system with no solutions and infinitely many solutions

In this article we study a class of generalised linear systems of difference equations with given boundary conditions and assume that the boundary value problem is non-consistent, i.e. it has infinite many or no solutions. We take into consideration the case that the coefficients are square constant matrices with the leading coefficient singular and provide optimal solutions. Numerical examples are given to justify our theory.

math.DS↗
arXiv2015

Causality of singular linear discrete time systems

We consider two type of systems, a linear singular discrete time system and a linear singular fractional discrete time system whose coefficients are square constant matrices. By assuming that the input vector changes only at equally space sampling instants we investigate and provide properties for causality between state and inputs and causality between output and inputs.

math.DS↗
arXiv2015

Solutions of Higher Order Homogeneous Linear Matrix Differential Equations: Singular Case

The main objective of this talk is to develop a matrix pencil approach for the study of an initial value problem of a class of singular linear matrix differential equations whose coefficients are constant matrices. By using matrix pencil theory we study the cases of non square matrices and of square matrices with an identically zero matrix pencil. Furthermore we will give necessary and sufficient conditions for existence and uniqueness of solutions and we will see when the uniqueness of solutions is not valid. Moreover we provide a numerical example.

math.DS↗
arXiv2014

A note on the relation between a singular linear discrete time system and a singular linear system of fractional nabla difference equations

In this article we focus our attention on the relation between a singular linear discrete time system and a singular linear system of fractional nabla difference equations whose coefficients are square constant matrices. By using matrix pencil theory, first we give necessary and sufficient condition to obtain a unique solution for the continuous time model. After by assuming that the input vector changes only at equally space sampling instants, we shall derive the corresponding discrete time state equation which yield the values of the solutions of the continuous time model which will connect the initial system to the singular linear system of fractional nabla difference equations.

math.DS↗
arXiv2014

Controllability and reachability of singular linear discrete time systems

The main objective of this article is to develop a matrix pencil approach for the study of the controllability and reachability of a class of linear singular discrete time systems. The description equation of a practical system may be established through selection of the proper state variables. Time domain analysis is the method of analyzing the system based on this description equation, through which we may gain a fair understanding of the system's structural features as well as its internal properties. Using time domain analysis, this article studies the fundamentals in system theory such as reachability and controllability.

math.OC↗