scholarly journals A Note on the Maximum Principle for Elliptic Differential Equations

Fritz John ◽  
1985 ◽  
pp. 107-110
Author(s):  
Fritz John
Keyword(s):  
Maximum Principle ◽  
Differential Equations ◽  
The Maximum Principle ◽  
Elliptic Differential Equations

Phragmèn-Lindelöf and Comparison Theorems for Elliptic-Parabolic Differential Equations

1967 ◽  
Vol 19 ◽  
pp. 864-871
Author(s):  
J. K. Oddson
Keyword(s):  
Maximum Principle ◽  
Differential Equations ◽  
Parabolic Equations ◽  
Comparison Theorems ◽  
Parabolic Differential Equations ◽  
The Maximum Principle ◽  
Comparison Functions

Theorems of Phragmèn-Lindelöf type and other related results for solutions of elliptic-parabolic equations have been given by numerous authors in recent years. Many of these results are based upon the maximum principle and the use of auxiliary comparison functions which are constructed as supersolutions of the equations under various conditions on the coefficients. In this paper we present an axiomatized treatment of these topics, replacing specific hypotheses on the nature of the coefficients of the equations by a single assumption concerning the maximum principle and another concerning the existence of positive supersolutions, in terms of which the theorems are stated.

scholarly journals The maximum principle for a type of hereditary semilinear differential equation

1994 ◽  
Vol 36 (2) ◽  
pp. 194-212
Author(s):  
Feiyue He
Keyword(s):  
Differential Equation ◽  
Optimal Control ◽  
Maximum Principle ◽  
Differential Equations ◽  
Optimal Control Problem ◽  
Control Problem ◽  
The Maximum Principle ◽  
Semilinear Differential Equation

AbstractAn optimal control problem governed by a class of delay semilinear differential equations is studied. The existence of an optimal control is proven, and the maximum principle and approximating schemes are found. As applications, three examples are discussed.

Application of Double Side Approach Method to the Solution of Fully Developed Laminar Flow in Duct Problems

2013 ◽  
Vol 29 (3) ◽  
pp. 471-479
Author(s):  
H.-W. Tang ◽  
Y.-T. Yang ◽  
C.-K. Chen
Keyword(s):  
Maximum Principle ◽  
Mathematical Programming ◽  
Laminar Flow ◽  
Differential Equations ◽  
Slip Boundary Condition ◽  
Optimization Method ◽  
The Maximum Principle ◽  
Weighted Residuals ◽  
Slip Boundary ◽  
Approach Method

AbstractThe double side approach method combines the method of weighted residuals (MWR) with mathematical programming to solve the differential equations. Once the differential equation is proved to satisfy the maximum principle, collocation method and mathematical programming are used to transfer the problem into a bilateral inequality. By utilizing Genetic Algorithms optimization method, the maximum and minimum solutions which satisfy the inequality can be found. Adopting this method, quite less computer memory and time are needed than those required for finite element method.In this paper, the incompressible-Newtonian, fully-developed, steady-state laminar flow in equilateral triangular, rectangular, elliptical and super-elliptical ducts is studied. Based on the maximum principle of differential equations, the monotonicity of the Laplace operator can be proved and the double side approach method can be applied. Different kinds of trial functions are constructed to meet the no-slip boundary condition, and it was demonstrated that the results are in great agreement with the analytical solutions or the formerly presented works. The efficiency, accuracy, and simplicity of the double side approach method are fully illustrated in the present study to indicate that the method is powerful for solving boundary value problems.

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