Oscillatory periodic solutions of differential-delay equations with multiple lags
Using known results about oscillatory periodic solutions of the delay differential equation \[ x'(t)=- \sum_{i=1}^n (- 1)^{[\frac{il}{n+1}]} f(x(t-i)) \] the author presents sufficient conditions under which the equation \[ x'(t)=- \sum_{i=1}^n \delta_i f(x(t-i)) \] admits at least one oscillatory periodic solution. Here \([a]\) indicates the maximal integer which is not greater than \(a\) and \(\delta_i\in \{-1,1\}\) for \(i=1,2,\dots, n\).
scientific article; zbMATH DE number 1077936