A criterion for bijectivity of mappings of Euclidean spaces

Abstract

We study the following problem introduced by J. Hadamard in 1906: to find sufficient conditions for a local diffeomorphism of an Euclidean space to be a global diffeomorphism. J. Hadamard introduced a celebrated integral condition which is a sufficient condition for the bijectivity of a local diffeomorphism. In this paper we improve the classical result of Hadamard giving a new sufficient condition for a $C^2$ mapping to be bijective.