Ein Pólyasches Momentenproblem und umhüllende asymptotische Potenzreihen.
Estimations asymptotiques des intervalles d'instabilité pour l'équation de Hill
Exponential-type Nagumo norms and summability of formal solutions of singular partial differential equations
In this paper, we study a class of first order nonlinear degenerate partial differential equations with singularity at . 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 -summability of the formal solutions. Furthermore, analytical solutions in conical domains are found for each type of these nonlinear singular PDEs.