Circular illustration of the synchronization problem between two limit cycles.

<p>The exemplary limit cycles (inner circle) and (outer circle) are introduced in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095195#pone-0095195-g004" target="_blank">Fig. 4</a>. (A) The degrees of freedom available for synchronization: The periods and the phase difference are both governed by the process (12), (13). The relative primitive durations are governed by the process (20), (21). (B) Perfect synchronization of the event pairs and , leading to coincident circles and events.