With the help of coincidence degree theory, sufficient conditions for existence of periodic solutions for a food chain model with functional responses on time scales are established. Keywords—time scales, food chain model, coincidence degree, periodic solutions.

In this paper, by utilizing the coincidence degree theorem a predator-prey model with modified Leslie-Gower Hollingtype II schemes and a deviating argument is studied. Some sufficient conditions are obtained for the existence of positive periodic solutions of the model. Keywords— Predator-prey model, Holling II type functional response, Positive periodic solution, Coincidence degree theorem

In this paper, a higher order nonlinear neutral functional differential equation with distributed delay is studied by using the continuation theorem of coincidence degree theory. Some new results on the existence of periodic solutions are obtained. Keywords—Neutral functional differential equation, higher order, periodic solution, coincidence degree theory

In this paper, the existence of 2 positive periodic solutions for n species non-autonomous Lotka-Volterra cooperative systems with harvesting terms is established by using Mawhin’s continuation theorem of coincidence degree theory and matrix inequality. An example is given to illustrate the effectiveness of our results. Keywords—Multiple positive periodic solutions; Nonautonomous Lotka-Volterra...

In this paper, the semi–ratio–dependent predator-prey system with nonmonotonic functional response on time scales is investigated. By using the coincidence degree theory, sufficient conditions for existence of periodic solutions are obtained. Keywords—Semi–ratio–dependent, predator–prey system, coincidence degree, time scales.

In this paper, a food chain model with Holling type II functional response on time scales is investigated. By using the Mawhin’s continuation theorem in coincidence degree theory, sufficient conditions for existence of periodic solutions are obtained. Keywords—Periodic solutions; food chain model; coincidence degree; time scales.

In this paper, by applying Mawhin’s continuation theorem of coincidence degree theory, we study the existence of almost periodic solutions for neural multi-delay logarithmic population model and obtain one sufficient condition for the existence of positive almost periodic solution for the above equation. An example is employed to illustrate our result. Keywords—Almost periodic solution; Multi-d...

This paper deals with a delayed single population model on time scales. With the assistance of coincidence degree theory, sufficient conditions for existence of periodic solutions are obtained. Furthermore, the better estimations for bounds of periodic solutions are established. Keywords—Coincidence degree, continuation theorem, periodic solutions, time scales

By using Mawhin’s continuation theorem of coincidence degree theory, we establish the existence of 2 positive periodic solutions for n species non-autonomous Lotka-Volterra competition systems with harvesting terms. An example is given to illustrate the effectiveness of our results. Keywords—Positive periodic solutions; Lotka-Volterra competition system; Coincidence degree; Harvesting term.

The main purpose of this paper is to investigate a discrete time three–species food chain system with ratio dependence. By employing coincidence degree theory and analysis techniques, sufficient conditions for existence of periodic solutions are established. Keywords—Food chain; ratio–dependent; coincidence degree; periodic solutions