www.ccsenet.org/jmr Journal of Mathematics Research Vol. 4, No. 1; February 2012
Existence of Multiple Positive Solutions of a Type of Impulsive
Functional Differential Equations
Luxia Li, Yuanhua Qiao (Corresponding author), Haili Wang
College of Applied Sciences, Beijing University of Technology
Ping Le Yuan 100, Beijing 100124, China
Tel: 86-10-6739-2182 E-mail: qiaoyuanhua@bjut.edu.cn
Received: October 20, 2011 Accepted: November 4, 2011 Published: February 1, 2012
doi:10.5539/jmr.v4n1p78 URL: http://dx.doi.org/10.5539/jmr.v4n1p78
The research is financed by Natural Science Foundation of China. No.61070149.
Abstract
In this paper, we consider the non-periodic boundary value problem for a type of first order impulsive functional dif-
ferential equation in Banach spaces. The existence of pulse in differential equations makes them an important area of
investigation. We make use of fixed point index theory on the cone to prove existence of positive solutions. The condi-
tions for existence of two and three positive solutions are given.
Keywords: Pulse equation, Periodic boundary value problems, Positive solution
1. Introduction and Preliminaries
In recent years, the theories of impulsive functional differential equations have been rapidly developed, and because such
equations may exhibit several real world phenomena in physics, biology, engineering, and so forth (Bainov & Simeonov,
1993; Lakshmikantham, Bainov & Simeonov, 1989; Bainov & Hristova, 1993), they have received much attention (Ding,
Mi & Han, 2005; Zhang & Liu, 2010),The periodic boundary value problem is an important research branch of the
impulsive functional differential equations. Some conclusions have been made (Zhang, Li, Jiang & Wang, 2006; Zhimin
& Weigao, 2002) about the existence of solutions and the multiplicity of positive solutions of the impulsive functional
differential equations with periodic boundary value problems. Whereas the non periodic boundary value occurs more
frequently in differential equations with pulse, researches are needed for the problem of existence of positive solutions
and multiplicity of such equations. In this paper£we restrict our attention to the study of the following first order impulsive
functional di fferential equations with non-periodic boundary value
u
′
(t) + M
2
u(t) = f (t, u
t
), t ∈ J = [0, T], t , t
k
, k = 1, 2, ··· , m
∆u(t
k
) = I
k
(u
t
k
), k = 1, ··· , m
u(0) = pu(T),
u(t) = u(0), t ∈ [−τ, 0],
(1)
Where, f : J × C
τ
is continuous. C
τ
:= {φ : [−τ, 0] → R ; φ(t) is continuous everywhere except a finite number of points
t, φ(t
+
), φ(t
−
) exist, and φ(t) = φ(t
−
)}. τ > 0 is a constant. u
t
∈ C
τ
, u
t
(θ) = u(t + θ), θ ∈ [−τ, 0], 0 < t
1
< t
2
< ··· < t
m
<
T, J
′
= J \{t
1
, t
2
, ··· , t
m
}, I
k
∈ C(C
τ
, R), ∆u(t
k
) = u(t
+
k
)−u(t
−
k
) indicates the jump at t = t
k
, u(t
+
k
) and u(t
−
k
) indicate the left
limit and the right limit of u(t) at t = t
k
, J
∗
= [−τ, T], p ∈ R. For φ ∈ C
τ
, its norm is defined as ||φ||
[−τ,0]
= max
θ∈[−τ,0]
|φ(θ)|.
The approaches used for the investigation of existence of positive solutions for differential equations with impulse are
monotone iterative technique and upper and lower solution method (Zhimin & She, 2002; Juan & Rosana, 2006; Luo
& Jing, 2008; He & He, 2004). Upper and lower solution method is often applied to discuss the minimal and maximal
solutions of such equations, and monotone iterative technique is usually used to prove the existence of solution. Recently
fixed point index theorem on cones in Banach space is introduced to investigate the multiplicity of solutions (Zhao, 2010).
In (Zhao, 2010), Zhao studied the problem (1), the results are established using the fixed point index theorem on the cone,
and they proved the existence of two solutions.
Motivated by the results mentioned above, in this paper, we give the conditions of the existence of two positive solutions
and three positive solutions of equations (1) using fixed point index theory on the cone.
2. Preliminaries
Throughout the rest of this paper, we always assume that the points of impulse t
k
are right-dense for each k =
78 ISSN 1916-9795 E-ISSN 1916-9809