• Journal of the Korean Mathematical Society
• /
• v.36 no.4
• /
• pp.757-771
• /
• 1999

We consider a system of functional differential equations x'(t)=F(t, $x_t$) and obtain conditions on a Liapunov functional and a Liapunov function to ensure the instability of the zero solution.

• Journal of the Korean Mathematical Society
• /
• v.34 no.1
• /
• pp.195-211
• /
• 1997

The purpose of this paper is to present the uniform asymptotic stability theorem and the uniform boundedness and uniform ultimate boundedness theorem for functional differential equations.

• Journal of the Korean Mathematical Society
• /
• v.42 no.4
• /
• pp.749-759
• /
• 2005

We apply a cone theoretic fixed point theorem and obtain conditions for the existence of positive periodic solutions of the system of functional differential equations $$x'(t)\;=\;A(t)x(t)+{\lambda}f(t,\;x(t-\tau(t))$$.

• Journal of applied mathematics & informatics
• /
• v.23 no.1_2
• /
• pp.445-453
• /
• 2007

This paper deals with the approximate controllability for the nonlinear functional differential equations with time delay and studies a variation of constant formula for solutions of the given equations.

• Bulletin of the Korean Mathematical Society
• /
• v.44 no.2
• /
• pp.315-330
• /
• 2007

In this paper, some hybrid fixed point theorems are proved which are further applied to first and second order neutral functional differential equations for proving the existence results for the extremal solutions under the mixed Lipschitz, compactness and monotonic conditions.

• Journal of the Chungcheong Mathematical Society
• /
• v.22 no.3
• /
• pp.325-332
• /
• 2009

Reducing the generalized logarithmic functional equations to differential equations in the sense of Schwartz distributions, we find the locally integrable solutions of the equations.

• Journal of applied mathematics & informatics
• /
• v.30 no.1_2
• /
• pp.147-160
• /
• 2012

In this paper, we establish some sufficient conditions for the existence of positive solutions for a class of multi-point boundary value problem for fractional functional differential equations involving the Caputo fractional derivative. Our results are based on two fixed point theorems. Two examples are also provided to illustrate our main results.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.11 no.1
• /
• pp.85-93
• /
• 2007

In this paper we prove the existence of mild solutions of a first order impulsive initial value problems for functional differential equations in Banach spaces. The results are obtained by using the Lerey-Schauder nonlinear alternative fixed point theorem.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.8
• /
• pp.726-730
• /
• 2001

In this paper, we consider the observability conditions for the following nonlinear fuzzy neutral functional differential equations in E$^{2}$$_{N}$.

• Journal of applied mathematics & informatics
• /
• v.37 no.1_2
• /
• pp.53-63
• /
• 2019

In this paper, we show the existence of solution of the neutral stochastic functional differential equations under non-Lipschitz condition, a weakened linear growth condition and a contractive condition. Furthermore, in order to obtain the existence of solution to the equation we used the Picard sequence.