The Completely Integrable Differential Systems are Essentially Linear Differential Systems

Abstract

El títol de la versió pre-print de l'article és: The Completely Integrable Differential Systems are Essentially Linear

Agraïments: Grant UNAB13-4E-1604, and from the recruitment program of high-end foreign experts of China. The second author is supported by Portuguese national funds through FCT-Fundação para a Ciência e a Tecnologia: Project PEst-OE/EEI/LA0009/2013 (CAMGSD). The third author is partially supported by NNSF of China Grant Number 11271252, by RFDP of Higher Education of China Grant Number 20110073110054 and by innovation program of Shanghai municipal education commission Grant 15ZZ012.

Let ˙x = f(x) be a C k autonomous differential system with k ∈ N ∪ {∞, ω} defined in an open subset Ω of R n. Assume that the system ˙x = f(x) is C r completely integrable, i.e. there exist n-1 functionally independent first integrals of class C r with 2 ≤ r ≤ k. If the divergence of system ˙x = f(x) is non-identically zero, then any Jacobian multiplier is functionally independent of the n - 1 first integrals. Moreover the system ˙x = f(x) is C r-1 orbitally equivalent to the linear differential system ˙y = y in a full Lebesgue measure subset of Ω. For Darboux and polynomial integrable polynomial differential systems we characterize their type of Jacobian multipliers.