In this paper, by using the fixed points of strict-set-contractions, we study the existence of at least one or two positive solutions to the generalize Sturm-Liouville four-point boundary value problem y''(t)+a(t)f(y (t))=θ, 0<t<1, αy(0)-βy1(0)=μ1y(ξ), γy(1)+δy'(1)=μ2y(η), in Banach space E, where θ is the zero element of E, 0<ξ<1, 0<η<1. As an application, we also give an example to demonstrate our results.

In this paper, by using the fixed points of strict-set-contractions, we study the existence of at least one or two positive solutions to the four-point boundary value problem y''(t)+a(t)f(y(t)=θ, 0<t<1, y(0)=μy(ξ), y(1)=βy(η) in Banach space E, where θ is zero element of E, 0<ξ≤η< 1, 0<μ< 1/1−ξ, 0<β<1/η and μξ(1-β)+(1-μ)(1-βη)>0. As an application, we also give one example to demonstrate our results.

this paper, we give existence and uniqueness results for solutions of multipoint boundary value problems of the form x'=ƒ(t,x(t))+e(t), t∈(0,1), m∑j=1/Ajx (ηj)=0, where ƒ: [0, 1] x Rn→Rn is s Carathdodory function, Ajs (j=1, 2,……,m) are constant square matrices of order n1, 0<η1<η2<…<ηm-1<ηm<1, and e(t) ∈L1([0, 1], Rn). The existence of solutions is proven by the coincidence degree theory. As an application, we also give one example to demonstrate our results.

In this paper, we consider the following second order ordinary differential equation x''=ƒ(t, x (t),x'(t))+e(t), t∈(0, 1), (1.1) subject to one of the following boundary value conditions: x(0)=m-2∑i=1/αix(ξi), x(1)=n-2∑j=1/βjx(ηj), (1.2) x'(0)=m-2∑i=1/αix1 (ξi), x'(1)=n-2∑j=1/βjx1 (ηj), (1.3) x'(0)=m-2∑i=1/αix1 (ξi), x'(1)=n-2∑j=1/βjx (ηj), (1.4) where αi (1≤i≤m-2), βj (1≤j≤n-2) ∈ R, 0<ξ1<ξ2<……<ξm-2<1, 0<η1<η2<……<ηn-2< 1. When all the ais have no the same sign and all the bjs have no the same sign, some existence results are given for (1.1) with boundary conditions (1.2)-(1.4) at resonance case. We also give some examples to demonstrate our results.

Sufficient conditions are derived for the controllability of nonlinear neutral evolution integrodifferential systems with infinite delay in a Banach space. The results are obtained by using the resolvent operators and the Schaefer fixed-point theorem. An example is given to illustrate the results.