Nonlinear equations on a Lie group

global results on some nonlinear partial differential equations for direct and inverse problems

در این رساله به بررسی رفتار جواب های رده ای از معادلات دیفرانسیل با مشتقات جزیی در دامنه های کراندار می پردازیم . این معادلات به فرم نیم-خطی و غیر خطی برای مسایل مستقیم و معکوس مورد مطالعه قرار می گیرند . به ویژه، تاثیر شرایط مختلف فیزیکی را در مساله، نظیر وجود موانع و منابع، پراکندگی و چسبندگی در معادلات موج و گرما بررسی می کنیم و به دنبال شرایطی می گردیم که متضمن وجود سراسری یا عدم وجود سراسر...

A Lie-Group Approach for Nonlinear Dynamic Systems Described by Implicit Ordinary Differential Equations

This contribution presents a Lie-group based approach for the accessibility and the observability problem of dynamic systems described by a set of implicit ordinary differential equations. It is shown that non-accessible or non-observable systems admit Lie-groups acting on their solutions such that distinguished parts of the system remain unchanged. The presented methods use the fact that the d...

On Lie Group Classification of Second{order Ordinary Difference Equations

On group equations

 Suppose $f$ is a map from a non-empty finite set $X$ to a finite group $G$. Define the map $zeta^f_G: Glongrightarrow mathbb{N}cup {0}$ by $gmapsto |f^{-1}(g)|$. In this article, we show that for a suitable choice of $f$, the map $zeta^f_G$ is a character. We use our results to show that the solution function for the word equation $w(t_1,t_2,dots,t_n)=g$ ($gin G$) is a character, where $w(t_1,...

Solving Nonlinear Differential Algebraic Equations by an Implicit GL(n, R) Lie-Group Method

Usually, n is larger than m. When m = 0, the DAEs reduce to the ODEs. There are many numerical methods used to solve ODEs, but only a few is used to solve DAEs [1–5]. A lot of engineering problems are modelled as a combination of ODEs and NAEs, which are abbreviated as differential algebraic equations (DAEs). The DAEs are both numerically and analytically difficult than the ODEs. Recently, ther...