Exact Meromorphic Solutions of Complex Algebraic Differential Equations

Exact Meromorphic Solutions of Complex Algebraic Differential Equations
Author: Kwok-Kin Wong
Publisher: Open Dissertation Press
Total Pages:
Release: 2017-01-26
Genre:
ISBN: 9781361281901

This dissertation, "Exact Meromorphic Solutions of Complex Algebraic Differential Equations" by Kwok-kin, Wong, 黃國堅, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: For any given complex algebraic ordinary differential equation (ODE), one major task of both pure and applied mathematicians is to find explicit meromorphic solutions due to their extensive applications in science. In 2010, Conte and Ng in [12] proposed a new technique for solving complex algebraic ODEs. The method consists of an idea due to Eremenko in [20] and the subequation method of Conte and Musette, which was first proposed in [9]. Eremenko's idea is to make use of the Nevanlinna theory to analyze the value distribution and growth rate of the solutions, from which one would be able to show that in some cases, all the meromorphic solutions of the studied differential equation are in a class of functions called "class W," which consists of elliptic functions and their degenerates. The establishment of solutions is then achieved by the subequation method. The main idea is to build subequations which have solutions that also satisfy the original differential equation, hoping that the subequations will be easier to solve. As in [12], the technique has been proven to be very successful in obtaining explicit particular meromorphic solutions as well as giving complete classification of meromorphic solutions. In this thesis, the necessary theoretical background, including the Nevanlinna theory and the subequation method, will be developed. The technique will then be applied to obtain all meromorphic stationary wave solutions of the real cubic Swift-Hohenberg equation (RCSH). This last part is joint work with Conte and Ng and will appear in Studies in Applied Mathematics [13]. RCSH is important in several studies in physics and engineering problems. For instance, RCSH is used as modeling equation for Rayleigh- B?nard convection in hydrodynamics [43] as well as in pattern formation [16]. Among the explicit stationary wave solutions obtained by the technique used in this thesis, one of them appears to be new and could be written down as a rational function composite with Weierstrass elliptic function. DOI: 10.5353/th_b4833021 Subjects: Differential-algebraic equations

Meromorphic Solutions of Complex Differential Equations

Meromorphic Solutions of Complex Differential Equations
Author: Chengfa Wu
Publisher:
Total Pages:
Release: 2017-01-27
Genre:
ISBN: 9781361348772

This dissertation, "Meromorphic Solutions of Complex Differential Equations" by Chengfa, Wu, 吳成發, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: The objective of this thesis is to study meromorphic solutions of complex algebraic ordinary differential equations (ODEs). The thesis consists of two main themes. One of them is to find explicitly all meromorphic solutions of certain class of complex algebraic ODEs. Since constructing explicit solutions of complex ODEs in general is very difficult, the other theme (motivated by the classical conjecture proposed by Hayman in 1996) is to establish estimations on the growth of meromorphic solutions in terms of Nevanlinna characteristic function. The tools from complex analysis that will be used have been collected in Chapter 1. Chapter 2 is devoted to introducing a method, which was first used by Eremenko and later refined by Conte and Ng, to give a classification of some complex algebraic autonomous ODEs. Under certain assumptions, based on local singularity analysis and Nevanlinna theory, this method shows that all meromorphic solutions of these ODEs if exist, must belong to 'class W', which consists of elliptic functions and their degenerations. Combined with knowledge from function theory, as shown by Demina and Kudryashov, it further allows us to find all of them explicitly and the details of the method will be illustrated by constructing new real meromorphic solutions of the stationary case of cubic-quintic Swift-Hohenberg equation. In Chapter 3, the same method is used to construct on R DEGREESn, n >= 2 some explicit Bryant solitons and on R DEGREESn\{0}, n >= 2 some Ricci solitons, and one of them turns out to be a new Ricci soliton on R DEGREES5\{0}. In addition, the completeness of corresponding metrics on the Ricci solitons that we have constructed are also discussed. In 1996, Hayman conjectured an upper bound on the growth, in terms of Nevanlinna characteristic function, of meromorphic solutions of complex algebraic ODEs. Related work in the literature towards this so-called classical conjecture is first reviewed in Chapter 4. The classical conjecture for three types of second order complex algebraic ODEs will then be verified by either giving a classification of the meromorphic solutions or obtaining them explicitly in Chapter 4. As the classical conjecture seems to be out of reach at present, we proposed in Chapter 5 to study a particular class of complex algebraic ODEs which can be factorized into certain form. On one hand, for these factorizable ODEs, it has been proven for the generic case that all their meromorphic solutions must be elliptic functions or their degenerations. On the other hand, the second order factorizable ODEs have been carefully studied so that their meromorphic solutions have been obtained explicitly except one case. This will allow the classical conjecture for most of the second order factorizable ODEs to be verified by employing Nevanlinna theory and certain qualitative results from complex differential equations. Finally, the classical conjecture has been shown to be sharp in certain cases. DOI: 10.5353/th_b5317034 Subjects: Differential equations

Methods for Constructing Exact Solutions of Partial Differential Equations

Methods for Constructing Exact Solutions of Partial Differential Equations
Author: Sergey V. Meleshko
Publisher: Springer Science & Business Media
Total Pages: 367
Release: 2006-06-18
Genre: Technology & Engineering
ISBN: 0387252657

Differential equations, especially nonlinear, present the most effective way for describing complex physical processes. Methods for constructing exact solutions of differential equations play an important role in applied mathematics and mechanics. This book aims to provide scientists, engineers and students with an easy-to-follow, but comprehensive, description of the methods for constructing exact solutions of differential equations.

Handbook of Exact Solutions for Ordinary Differential Equations

Handbook of Exact Solutions for Ordinary Differential Equations
Author: Valentin F. Zaitsev
Publisher: CRC Press
Total Pages: 815
Release: 2002-10-28
Genre: Mathematics
ISBN: 1420035339

Exact solutions of differential equations continue to play an important role in the understanding of many phenomena and processes throughout the natural sciences in that they can verify the correctness of or estimate errors in solutions reached by numerical, asymptotic, and approximate analytical methods. The new edition of this bestselling handboo

Meromorphic Solutions of Generalized Algebraic Differential Equations

Meromorphic Solutions of Generalized Algebraic Differential Equations
Author: Chung-Chun Yang
Publisher:
Total Pages: 13
Release: 1971
Genre:
ISBN:

The rate of growth of meromorphic functions f, which are solutions of algebraic differential equations whose coefficients a(z) are arbitrary meromorphic functions, is investigated. By a method based on Nevanlinna's theory of meromorphic functions, it has been shown that if f'/f has infinity as its Nevanlinna exceptional values, then the ratio T(r, f'/f)/T(r, a(z)), as r approaches infinity outside a set of r values of finite measure, is bounded for at least one of the coefficients a(z). (Author).