Formal and Convergent Solutions of Singular Partial Differential Equations.
Formal solutions of nonlinear first order totally characteristic type PDE with irregular singularity
In this paper, we calculate the formal Gevrey index of the formal solution of a class of nonlinear first order totally characteristic type partial differential equations with irregular singularity in the space variable. We also prove that our index is the best possible one in a generic case.
Fourier problem with bounded Baire data
The Fourier problem on planar domains with time moving boundary is considered using integral equations. Solvability of those integral equations in the space of bounded Baire functions as well as the convergence of the corresponding Neumann series are proved.
Fundamental solution for operators preserving a quadratic form
Funktionenfamilien mit einem Maximumprinzip und elliptische Differentialgleichungen II.