“…It is also important to study chaos in general relativity because the Einstein equations are nonlinear. Many authors have reported chaos in general relativity [6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]. As for a realistic astrophysical object, there has been a discussion whether or not chaos occurs in a compact binary system [21,22,23].…”