On the uniqueness of limit cycles for Liénard equations: the legacy of G. Sansone

  • Marco Sabatini
  • Gabriele Villari
Keywords: Liénard equation, Sansone, Massera, uniqueness, limit cycle.


We give an account of the results about limit cycle’s uniqueness for Liénard equations, starting from Levinson-Smith’s one to the most recent ones. We present a new uniqueness theorem in the line of Sansone-Massera’s geometrical approach.