Padé Methods for Painlevé Equations: 42 (SpringerBriefs in Mathematical Physics, 42)

Padé Methods for Painlevé Equations: 42 (SpringerBriefs in Mathematical Physics, 42)
by: Hidehito Nagao (Author),Yasuhiko Yamada(Author)
Edition:1st ed. 2021
Publication Date: 2 Sept. 2021
Language:English
Print Length:98 pages
ISBN-10:9811629978
ISBN-13:9789811629976
Book Description
The isomonodromic deformation equations such as the Painlevé and Garnier systems are an important class of nonlinear differential equations in mathematics and mathematical physics. For discrete analogs of these equations in particular, much progress has been made in recent decades. Various approaches to such isomonodromic equations are known: the Painlevé test/Painlevé property, reduction of integrable hierarchy, the Lax formulation, algebro-geometric methods, and others. Among them, the Padé method explained in this book provides a simple approach to those equations in both continuous and discrete cases.For a given function f(x), the Padé approximation/interpolation supplies the rational functions P(x), Q(x) as approximants such as f(x)~P(x)/Q(x). The basic idea of the Padé method is to consider the linear differential (or difference) equations satisfied by P(x) and f(x)Q(x). In choosing the suitable approximation problem, the linear differential equations give the Lax pair for some isomonodromic equations. Although this relation between the isomonodromic equations and Padé approximations has been known classically, a systematic study including discrete cases has been conducted only recently. By this simple and easy procedure, one can simultaneously obtain various results such as the nonlinear evolution equation, its Lax pair, and their special solutions. In this way, the method is a convenient means of approaching the isomonodromic deformation equations.
About the Author
Review “The monograph under review explores an important connection between integrable systems and approximation theory: the appearance of integrable systems in Padé approximation and interpolation problems. Both authors have contributed plenty of work in this direction together and individually, and one can view this work as a pedagogical guide to this rich area. … The monograph is well organized, and has plenty of examples motivating the discussion and demonstrating the power of the Padé method … .” (Ahmad Bassam Barhoumi, Mathematical Reviews, September, 2022)