The number of periodic solutions of polynomial differential equations
The main result of this paper is as follows: The scalar differential equation \[ {dx\over dt}= x^{2n+1}+ a(t) x^2+ b(t) x+ c(t), \] where \(a\), \(b\) and \(c\) are smooth \(T\)-periodic functions, has at most three \(T\)-periodic solutions.
scientific article; zbMATH DE number 1407581