Inverse limits associated with the forced van der Pol equation

Abstract

In “Qualitative Analysis of the Periodically Forced Relaxation Oscillations,” Mark Levi (Mem. Am. Math. Soc. 32, No. 244, July 1981) gives a nice geometric description of annulus maps associated with the first return map for the forced van der Pol equation ex+Φ(x)x+ex=bp(t). In this paper, it is shown that for certain parameter valuesb, the full attracting sets of the annulus maps described by Levi can be realized as inverse limits of circles. Furthermore, we show that the annulus map is topologically conjugate to the shift homeomorphism on the inverse limit space.