Periodic solutions of semilinear equations at resonance with a $2n$-dimensional kernel

M. Shiwang, Huazhong University of Science and Technology, Wuhan, P. R. China
Z. Wang, Hunan University, Changsha, P. R. China

E. J. Qualitative Theory of Diff. Equ., No. 2. (1999), pp. 1-13.

Abstract: In this paper, we obtain some sufficient conditions for the existence of $2\pi$-periodic solutions of some semilinear equations at resonance where the kernel of the linear part has dimension $2n(n\ge 1)$. Our technique essentially bases on the Brouwer degree theory and Mawhin's coincidence degree theory.

You can download the full text of this paper in DVI, PostScript or PDF format, or have a look at the Zentralblatt or the Mathematical Reviews entry of this paper.