On the rings of formal solutions of polynomial differential equations

Autor: Maria-Angeles Zurro
Rok vydání: 1998
Předmět:
Zdroj: Banach Center Publications. 44:277-292
ISSN: 1730-6299
0137-6934
DOI: 10.4064/-44-1-277-292
Popis: Introduction. The Gevrey series appeared as formal solutions of partial differential equations of second order ([G]). In 1903 Maillet ([Mi]) proved that the formal solutions of ordinary differential equations with polynomial coefficients are of this type. Afterwards, Malgrange ([Ml]) and J. Cano ([Ca]) generalized this result to ordinary differential equations with analytic and Gevrey coefficients respectively. But for partial differential equations the analogous result is not yet achieved for any partial differential equation with polynomial coefficients; nevertheless there are some important results: see Ouchi ([O]). The semianalytic geometry with Gevrey conditions to the border is studied in the article of Tougeron [T]. He generalized the basic theorems of the semianalytic geometry to this case. As far as we know, a study of the algebraic properties of this series has not yet been done. This work shows the basic algebraic properties of these rings. In particular, they are noetherian and henselian. The basic tools we use here are the pseudo-Banach structure they have, and the formal Borel transform. This transform changes the Gevrey series by
Databáze: OpenAIRE