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Convergence of formal solutions of first order singular nonlinear partial differential equations in the complex domain

Masatake Miyake, Akira Shirai (2000)

Annales Polonici Mathematici

We study the convergence or divergence of formal (power series) solutions of first order nonlinear partial differential equations    (SE) f(x,u,Dx u) = 0 with u(0)=0. Here the function f(x,u,ξ) is defined and holomorphic in a neighbourhood of a point ( 0 , 0 , ξ 0 ) x n × u × ξ n ( ξ 0 = D x u ( 0 ) ) and f ( 0 , 0 , ξ 0 ) = 0 . The equation (SE) is said to be singular if f(0,0,ξ) ≡ 0 ( ξ n ) . The criterion of convergence of a formal solution u ( x ) = | α | 1 u α x α of (SE) is given by a generalized form of the Poincaré condition which depends on each formal solution. In the case where the formal...

Convergence of power series along vector fields and their commutators; a Cartan-Kähler type theorem

B. Jakubczyk (2000)

Annales Polonici Mathematici

We study convergence of formal power series along families of formal or analytic vector fields. One of our results says that if a formal power series converges along a family of vector fields, then it also converges along their commutators. Using this theorem and a result of T. Morimoto, we prove analyticity of formal solutions for a class of nonlinear singular PDEs. In the proofs we use results from control theory.

Explicit solution for Lamé and other PDE systems

Alexei Rodionov (2006)

Applications of Mathematics

We provide a general series form solution for second-order linear PDE system with constant coefficients and prove a convergence theorem. The equations of three dimensional elastic equilibrium are solved as an example. Another convergence theorem is proved for this particular system. We also consider a possibility to represent solutions in a finite form as partial sums of the series with terms depending on several complex variables.

Explicit Solutions of Nonlocal Boundary Value Problems, Containing Bitsadze-Samarskii Constraints

Tsankov, Yulian (2010)

Fractional Calculus and Applied Analysis

MSC 2010: 44A35, 35L20, 35J05, 35J25In this paper are found explicit solutions of four nonlocal boundary value problems for Laplace, heat and wave equations, with Bitsadze-Samarskii constraints based on non-classical one-dimensional convolutions. In fact, each explicit solution may be considered as a way for effective summation of a solution in the form of nonharmonic Fourier sine-expansion. Each explicit solution, may be used for numerical calculation of the solutions too.

Exponential-type Nagumo norms and summability of formal solutions of singular partial differential equations

Zhuangchu Luo, Hua Chen, Changgui Zhang (2012)

Annales de l’institut Fourier

In this paper, we study a class of first order nonlinear degenerate partial differential equations with singularity at ( t , x ) = ( 0 , 0 ) C 2 . Using exponential-type Nagumo norm approach, the Gevrey asymptotic analysis is extended to case of holomorphic parameters in a natural way. A sharp condition is then established to deduce the k -summability of the formal solutions. Furthermore, analytical solutions in conical domains are found for each type of these nonlinear singular PDEs.

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