• 충청수학회지
• /
• 제23권4호
• /
• pp.793-800
• /
• 2010

We investigate the existence and uniqueness of almost automorphic mild solutions of the semilinear abstract differential equations.

• Kyungpook Mathematical Journal
• /
• 제61권3호
• /
• pp.559-581
• /
• 2021

In this paper, we establish the existence of solutions and the approximate controllability for the semilinear neutral differential control system under natural assumptions such as the local Lipschitz continuity of nonlinear term. First, we deal with the regularity of solutions of the neutral control system using fractional powers of operators. We also consider the approximate controllability for the semilinear neutral control equation, with a control part in place of a forcing term, using conditions for the range of the controller without the inequality condition as in previous results.

• 대한수학회지
• /
• 제50권3호
• /
• pp.627-639
• /
• 2013

The goal of this paper is to obtain the regularity and the existence of solutions of a retarded semilinear differential equation with nonlocal condition by applying Schauder's fixed point theorem. We construct the fundamental solution, establish the H$\ddot{o}$lder continuity results concerning the fundamental solution of its corresponding retarded linear equation, and prove the uniqueness of solutions of the given equation.

• 대한수학회지
• /
• 제58권5호
• /
• pp.1279-1298
• /
• 2021

The aim of this paper is to prove the existence of the global attractor of the Cauchy problem for a semilinear degenerate hyperbolic equation involving strongly degenerate elliptic differential operators. The attractor is characterized as the unstable manifold of the set of stationary points, due to the existence of a Lyapunov functional.

• 대한수학회지
• /
• 제39권5호
• /
• pp.775-782
• /
• 2002

In this paper we prove the existence of mild soultions for semilinear differential equations in a Banach space. The results are obtained by using the semigroup theory and the Schaefer fixed point theorem. An example is provided to illustrate the theory.

• 대한수학회논문집
• /
• 제28권3호
• /
• pp.559-569
• /
• 2013

The purpose of this paper is to establish existence, uniqueness and a variation of constant formula of solutions for semilinear partial functional differential equations with unbounded delays and nonlinear part involving integro differetial terms.

• 충청수학회지
• /
• 제34권3호
• /
• pp.189-207
• /
• 2021

In this paper, we consider the approximate controllability for a class of semilinear integro-differential functional control equations in which nonlinear terms of given equations satisfy quasi-homogeneous properties. The main method used is to make use of the surjective theorems that is similar to Fredholm alternative in the nonlinear case under restrictive assumptions. The sufficient conditions for the approximate controllability is obtain which is different from previous results on the system operator, controller and nonlinear terms. Finally, a simple example to which our main result can be applied is given.

• 대한수학회보
• /
• 제55권1호
• /
• pp.63-79
• /
• 2018

In this paper, we first consider the existence and regularity of solutions of the semilinear control system under natural assumptions such as the local Lipschtiz continuity of nonlinear term. Thereafter, we will also establish the approximate controllability for the equation when the corresponding linear system is approximately controllable.

• Kyungpook Mathematical Journal
• /
• 제47권2호
• /
• pp.191-202
• /
• 2007

By using the weighted averaging techniques, we establish oscillation criteria for the second order damped quasilinear elliptic differential equation $$\sum_{i,j=1}^{N}D_i(a_{ij}(x){\parallel}Dy{\parallel}^{p-2}D_jy)+{\langle}b(x),\;{\parallel}Dy{\parallel}^{p-2}Dy{\rangle}+c(x)f(y)=0,\;p>1$$. The obtained theorems include and improve some existing ones for the undamped halflinear partial differential equation and the semilinear elliptic equation.

• 한국수학사학회지
• /
• 제16권2호
• /
• pp.117-128
• /
• 2003

We investigate the origin and recent history for fuzzy equations. And we introduce the existence theorems of solutions for the fuzzy differential equation with infinite delays and fuzzy functional integral equations. We will also recent researches for controllability of sobolev-type semilinear integro-differential fuzzy system.