Seshadev Padhi and Smita Pati

Positive Periodic Solutions for a Nonlinear Functional Differential Equation

abstract:
In this paper, sufficient conditions have been obtained for the existence of at least two positive periodic solutions of the Nicholson's Blowflies model
$$ x^{\prime}(t)=-a(t)x(t)+p(t)x^{m}(t-\tau(t))e^{-\gamma(t)x^{n}(t-\tau(t))}. $$
The Leggett-Williams multiple fixed point theorem has been used to prove our results.

Mathematics Subject Classification: 34K40, 34C10, 34C25

Key words and phrases: Periodic solution, nonnegative solution