Abstract. In this paper we consider a class of higher dimensional differential systems in R n which have a two dimensional center manifold at the origin with a pair of pure imaginary eigenvalues. First we characterize the existence of either analytic or C ∞ inverse Jacobian multipliers of the systems around the origin, which is either a center or a focus on the center manifold. Later we study the cyclicity of the system at the origin through Hopf bifurcation by using the vanishing multiplicity of the inverse Jacobian multiplier.
Background and statement of the main resultsFor real planar differential systems, the problems on center-focus and Hopf bifurcation are classical and related. They are important subjects in the bifurcation theory and also in the study of the Hilbert's 16th problem [6,7,15,17].For planar non-degenerate center, Poincaré provided an equivalent characterization. Poincaré center Theorem. For a real planar analytic differential system with the origin as a singularity having a pair of pure imaginary eigenvalues, then the origin is a center if and only if the system has a local analytic first integral, and if and only if the system is analytically equivalent tȯwith g(uv) without constant terms, where we have used the conjugate complex coordinates instead of the two real ones.This result has a higher dimensional version, see for instance [13,18,20], which characterizes the equivalence between the analytic integrability and the existence of analytic normalization of analytic differential systems to its Poincaré-Dulac normal form of a special type.Reeb [14] in 1952 provided another characterization on planar centers via inverse integrating factor. Recall that a function V is an inverse integrating factor of a planar differential system if 1/V is an integrating factor of the