Triple Positive Solutions for nth-Order Impulsive Differential Equations with Integral Boundary Conditions and p-Laplacian

In this paper, we study a class of nth-order boundary value problems for impulsive differential equations with integral boundary conditions and p-Laplacian. The Leray–Schauder fixed point theorem is used to investigate the existence of at least one positive solution. We also consider the existence of at least three positive solutions by using a fixed-point theorem in a cone due to Avery-Peterson. As an application, we give an example to demonstrate our results.     

Multiple positive solutions for multi-point boundary value problems with a p-Laplacian on the half-line

This paper deals with the existence of multiple positive solutions for multi-point boundary value problems with p-Laplacian on infinite intervals. By using three fixed point theorems in cones, especially a five functionals fixed point theorem, we obtain the sufficient conditions for the existence of at least one, two and three positive solutions, respectively. Two examples are also given in this paper to illustrate the main results.     

Positive solutions for three-point one-dimensional p-Laplacian boundary value problems with advanced arguments

This paper considers the existence of positive solutions for advanced differential equations with one-dimensional p-Laplacian. To obtain the existence of at least three positive solutions we use a fixed point theorem due to Avery and Peterson.     

Existence regions of positive periodic solutions for a discrete hematopoiesis model with unimodal production functions

A discrete model describing the increase and decrease of blood cells is considered in this paper. This hematopoiesis model is a discretization of a delay differential equation with unimodal production function whose coefficients and delays are periodic discrete functions with ω-period. This paper is concerned with the existence of positive ω-periodic solutions. Our results are proved by using the well-known continuation theorem of coincidence degree theory. The existence range of the positive ω-periodic solutions is also clarified. A concrete example and its simulation are also given to illustrate our result. Finally, we examine how positive numbers and coefficients making up our model influence the upper and lower limits of blood cell counts.     

Impulsive Boundary Value Problems with Riemann–Stieltjes Δ-Integral Conditions and <Emphasis Type="Italic">p</Emphasis>-Laplacian Operator on Timescales

In this paper, we study the impulsive boundary value problems with Riemann–Stieltjes Δ-integral conditions and p-Laplacian operator on timescales. Using the Leray–Schauder fixed point theorem and the nonlinear alternative of Leray–Schauder type, we get the existence of at least one positive solution. We also consider the existence of at least three positive solutions using a new fixed point theorem. Finally, we give an example to show the feasibility of our main results.     

具有单调递增同胚和正同态算子二阶三点边值问题三个正解的存在性

利用Leggett-Williams不动点定理研究了一类具有单调递增同胚和正同态算子的边值问题,得到了三个正解存在的一组充分条件.     

Multiple positive solutions of n-point boundary value problems on the half-line in Banach spaces

In this paper, the fixed point index theory is used to investigate the existence of at least two positive solutions of n-point boundary value problem on the half-line in a Banach space. As an application, we give an example to demonstrate our results.     

The effects of indefinite nonlinear boundary conditions on the structure of the positive solutions set of a logistic equation

We investigate a semilinear elliptic equation with a logistic nonlinearity and an indefinite nonlinear boundary condition, both depending on a parameter λ. Overall, we analyze the effect of the indefinite nonlinear boundary condition on the structure of the positive solutions set. Based on variational and bifurcation techniques, our main results establish the existence of three nontrivial non-negative solutions for some values of λ, as well as their asymptotic behavior. These results suggest that the positive solutions set contains an S-shaped component in some case, as well as a combination of a C-shaped and an S-shaped components in another case.     

A priori estimates and existence of positive solutions for strongly nonlinear problems

In this paper we study the existence of positive solutions for a nonlinear Dirichlet problem involving the m-Laplacian. The nonlinearity considered depends on the first derivatives; in such case, variational methods cannot be applied. So, we make use of topological methods to prove the existence of solutions. We combine a blow-up argument and a Liouville-type theorem to obtain a priori estimates. Some Harnack-type inequalities which are needed in our reasonings are also proved.     

Existence of positive periodic solutions for neutral multi-delay logarithmic population model

In the paper, a new result is obtained for the existence of positive periodic solutions to a neutral multi-delay logarithmic population model. Our analysis mainly relies on an abstract continuous theorem of k-set contractive operator. We also give an example to illustrate the applicability of our results.     

A necessary and sufficient condition for 2nth-order singular super-linear m-point boundary value problems

In this paper, we study the existence of positive solutions for singular super-linear m-point boundary value problems of 2nth-order ordinary differential equations. A necessary and sufficient condition for the existence of C2n−2[0,1] positive solutions as well as C2n−1[0,1] positive solutions is given by means of the fixed point theorems on cones.     

Triple positive solutions to third order three-point BVP with increasing homeomorphism and positive homomorphism

In this paper, we investigate the existence of triple positive solutions for nonlinear differential equations boundary value problems with increasing homeomorphism and positive homomorphism operator. By using fixed point theorems in cones, we establish results on the existence of three positive solutions with suitable growth conditions imposed on the nonlinear term. As applications, two examples are given to demonstrate our result. The conclusions in this paper essentially extend and improve the known results.     

The Positive Solutions for Integral Boundary Value Problem of Fractional <Emphasis Type="Italic">p</Emphasis>-Laplacian Equation with Mixed Derivatives

In this paper, we consider a class of integral boundary value problems of fractional p-Laplacian equation, which involve both Riemann–Liouville fractional derivative and Caputo fractional derivative. By using the generalization of Leggett–Williams fixed point theorem, some new results on the existence of at least three positive solutions to the boundary value problems are obtained. Finally, some examples are presented to illustrate the extensive potential applications of our main results.     

Existence of Positive Solutions for Nonlinear Second-Order Impulsive Boundary Value Problems on Time Scales

This paper is concerned with the existence of positive solutions of second-order impulsive boundary value problem with integral boundary conditions on time scales. Existence results of at least three positive solutions are established via a new fixed point theorem in a cone. Also, an example is given to illustrate the effectiveness of our result.     

Existence of positive solutions for a second-order ordinary differential system

In this paper we consider the existence of positive solutions for a second-order ordinary differential system, where the nonlinear term is superlinear in one equation and sublinear in the other equation. By constructing a cone K₁×K₂ which is the Cartesian product of two cones in space C[0,1] and computing the fixed point index in K₁×K₂, we establish the existence of positive solutions for the system. We remark that, differently from the literature, we deal with our problem on the Cartesian product of two cones, in which the feature of two equations can be exploited better.     

Positive solutions of nonlinear m-point BVP for an increasing homeomorphism and positive homomorphism with sign changing nonlinearity on time scales

In this paper, by using fixed point theorems in cones, some new existence criteria for positive solutions of the nonlinear m-point boundary value problem with an increasing homeomorphism and positive homomorphism are presented. The nonlinear term f is allowed to change sign. In particular, our criteria generalize and improve some known results [20] and the obtained conditions are different from related literature [16], [17], [23]. As an application, one representative example to demonstrate our results are given.     

Multiple periodic solutions of a ratio-dependent predator–prey model

A delayed ratio-dependent predator–prey model with non-monotone functional response is investigated in this paper. Some new and interesting sufficient conditions are obtained for the global existence of multiple positive periodic solutions of the ratio-dependent model. Our method is based on Mawhin’s coincidence degree and some estimation techniques for the a priori bounds of unknown solutions to the equation Lx = λNx. An example is represented to illustrate the feasibility of our main result.     

Positive solutions for m-point boundary-value problems with one-dimensional p-Laplacian

In this paper, we investigate the existence of positive solutions for a classes of m-point boundary value problems with p-Laplacian. By applying a monotone iterative technique, some sufficient conditions for the existence of twin positive solutions are established.     

Positive solutions of the system for nth-order singular nonlocal boundary value problems

The paper deals with the existence and multiplicity of positive solutions to systems of nth-order singular nonlocal boundary value problems. The main tool used in the proof is fixed point index theory in cone. Some limit type conditions for ensuring the existence of positive solutions are given.     

NONEXISTENCE AND EXISTENCE OF POSITIVE SOLUTIONS FOR 2nTH-ORDER SINGULAR SUPERLINEAR PROBLEMS WITH STRUM-LIOUVILLE BOUNDARY CONDITIONS

This paper investigates a class of 2nth-order singular superlinear problems with Strum-Liouville boundary conditions. We obtain a necessary and sufficient condition for the existence of C 2 n- 2 [0, 1] positive solutions, and a sufficient condition, a necessary condition for the existence of C 2 n-1 [0, 1] positive solutions. Relations between the positive solutions and the Green’s functions are depicted. The results are used to judge nonexistence or existence of positive solutions for given boundary value problems.