# American Institute of Mathematical Sciences

December  2009, 25(4): 1129-1141. doi: 10.3934/dcds.2009.25.1129

## Polynomial differential equations with small coefficients

 1 Department of Mathematics, West Los Angeles College, Los Angeles, CA 90230-3519, United States

Received  January 2009 Revised  May 2009 Published  September 2009

Classes of polynomial non-autonomous differential equations of degree $n$ are considered. An explicit bound on the size of the coefficients is given which implies that each equation in the class has exactly $n$ complex periodic solutions. In most of the classes the upper bound can be improved when we consider real periodic solutions. We present a proof to a recent conjecture about the number of periodic solutions. The results are used to give upper bounds for the number of limit cycles of polynomial two-dimensional systems.
Citation: M. A. M. Alwash. Polynomial differential equations with small coefficients. Discrete & Continuous Dynamical Systems - A, 2009, 25 (4) : 1129-1141. doi: 10.3934/dcds.2009.25.1129
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