Existence of nontrivial periodic solutions for first order functional differential equations

In this paper, in the case of not requiring the nonlinear terms to be non-negative the existence of nontrivial periodic solutions for the first order functional differential equations is considered by using the partial ordering theory.     

Existence of positive periodic solutions of first order neutral differential equations with variable coefficients

This work deals with the existence of positive $\omega$-periodic solutions for the first order neutral differential equation. The results are established using Krasnoselskii’s fixed point theorem. An example is given to support the theory.     

Existence of periodic solutions for a class of first order delay differential equations dealing with vectors

By the weak linking theorem and the local linking theorem, we study the existence of periodic solutions for the following delay non-autonomous systems

(1)     

Existence and uniqueness of periodic solutions for a kind of first order neutral functional differential equations

In this paper, we use the coincidence degree theory to establish new results on the existence and uniqueness of T-periodic solutions for the first order neutral functional differential equation of the form

(x(t)+Bx(t−δ)^)′=g₁(t,x(t))+g₂(t,x(t−τ))+p(t).     

Existence of positive periodic solutions to nonlinear second order differential equations

In this paper, we discuss the existence of positive periodic solutions to the nonlinear differential equation $u^{″}\left(t\right)+a\left(t\right)u\left(t\right)=f(t,u\left(t\right))\text{,}t\in R\text{,}$ where $a:R\to [0,+\infty )$ is an $\omega$-periodic continuous function with $a\left(t\right)⁄\equiv 0$, $f:R\times [0,+\infty )\to [0,+\infty )$ is continuous and $f(\cdot ,u):R\to [0,+\infty )$ is also an $\omega$-periodic function for each $u\in [0,+\infty )$. Using the fixed point index theory in a cone, we get an essential existence result because of its involving the first positive eigenvalue of the linear equation with regard to the above equation.     

Existence of positive periodic solutions of periodic boundary value problem for second order ordinary differential equations

In this paper the existence of positive solutions are obtained for a class of second order differential equations. The proof is based on the fixed point index theory in cones.     

On periodic solutions for even order differential equations

A class of sufficient conditions are obtained for the existence of a unique 2π$2\pi$-periodic solution of even order differential equations, employing an initial value problem.     

Pseudo almost periodic solutions for a class of first order differential iterative equations

This paper is concerned with a class of first order differential iterative equations. Under proper conditions, we employ a novel argument to establish a criterion on the existence of pseudo almost periodic solutions. The obtained result complements with some existing ones.     

Positive periodic solutions of singular systems of first order ordinary differential equations

The existence and multiplicity of positive periodic solutions for first non-autonomous singular systems are established with superlinearity or sublinearity assumptions at infinity for an appropriately chosen parameter. The proof of our results is based on the Krasnoselskii fixed point theorem in a cone.     

Existence of positive periodic solutions of first‐order neutral differential equations

This paper presents the existence of positive periodic solutions for first‐order neutral differential equation with distributed deviating arguments. We apply Krasnoselskii's fixed point theorem to obtain our results. An example is given to support the theory. Copyright © 2016 John Wiley & Sons, Ltd.     

EXISTENCE OF SOLUTIONS FOR SECONDORDER IMPULSIVE DIFFERENTIAL EQUATIONS

In this paper, we apply the coincidence degree theory to study nonlinear second orderimPulsive periodic boundary value problems (PBVP), and show some sufficient conditions for the existence of solutions.     

Existence theory for first order discontinuous functional differential equations

We prove the existence of extremal solutions for a first order functional differential equation subject to nonlinear boundary conditions of functional type. Moreover, the functions that define our problem are allowed to be discontinuous. The proof of our main result is based on a generalized iterative technique.

     

具偏差变元高阶Lienard方程周期解存在性

利用重合度理论,研究了一类具偏差变元高阶L ienard型方程周期解的存在性,获得了该方程至少存在一个周期解的充分条件.     

Asymptotically almost periodic solutions of abstract retarded functional differential equations of first order

We establish the existence of asymptotically almost periodic mild solutions for a class of semi-linear first-order abstract retarded functional differential equations with infinite delay.     

Existence of positive periodic solutions for second-order functional differential equations

In this paper, we show the existence of positive $T$ -periodic solutions of second-order functional differential equations $u^{\prime \prime }(t)-\rho ^2u(t)+\lambda g(t)f(u(t-\tau (t)))=0,\ \ t\in \mathbb R , $ where $\rho >0$ is a constant, $g\in C(\mathbb R ,[0,\infty ))$ , $\tau \in C(\mathbb R ,\mathbb R )$ are $T$ -periodic functions, $f\in C([0,\infty ),[0,\infty ))$ and $\lambda $ is a positive parameter. Our approach based on global bifurcation theorem.     

Existence of multiple positive periodic solutions for functional differential equations

In our paper, by employing Krasnoselskii fixed point theorem, we investigate the existence of multiple positive periodic solutions for functional differential equations