CONFIGURATIONS OF FANS AND NESTS OF LIMIT CYCLES FOR POLYNOMIAL VECTOR FIELDS IN THE PLANE

Abstract In the set of limit cycles of a polynomial vector field X = (P, Q) in the plane two equivalence relations are defined. Their classes of equivalence introduce the notions of fan and nest of limit cycles. By using them we obtain information about the configurations of limit cycles of X taking into account the degrees of the polynomials P and Q.