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Explicit solutions for boundary value problems related to the operator equations X ( 2 ) - A X = 0

Lucas Jódar, Enrique A. Navarro (1991)

Applications of Mathematics

Cauchy problem, boundary value problems with a boundary value condition and Sturm-Liouville problems related to the operator differential equation X ( 2 ) - A X = 0 are studied for the general case, even when the algebraic equation X 2 - A = 0 is unsolvable. Explicit expressions for the solutions in terms of data problem are given and computable expressions of the solutions for the finite-dimensional case are made available.

Explosive solutions of semilinear elliptic systems with gradient term.

Marius Ghergu, Vicentiu Radulescu (2003)

RACSAM

Estudiamos la existencia de soluciones del sistema elíptico no lineal Δu + |∇u| = p(|x|)f(v), Δv + |∇v| = q(|x|)g(u) en Ω que explotan en el borde. Aquí Ω es un dominio acotado de RN o el espacio total. Las nolinealidades f y g son funciones continuas positivas mientras que los potenciales p y q son funciones continuas que satisfacen apropiadas condiciones de crecimiento en el infinito. Demostramos que las soluciones explosivas en el borde dejan de existir si f y g son sublineales. Esto se tiene...

Extremal properties of distance-based graph invariants for k -trees

Minjie Zhang, Shuchao Li (2018)

Mathematica Bohemica

Sharp bounds on some distance-based graph invariants of n -vertex k -trees are established in a unified approach, which may be viewed as the weighted Wiener index or weighted Harary index. The main techniques used in this paper are graph transformations and mathematical induction. Our results demonstrate that among k -trees with n vertices the extremal graphs with the maximal and the second maximal reciprocal sum-degree distance are coincident with graphs having the maximal and the second maximal reciprocal...

Extremal solutions and relaxation for second order vector differential inclusions

Evgenios P. Avgerinos, Nikolaos S. Papageorgiou (1998)

Archivum Mathematicum

In this paper we consider periodic and Dirichlet problems for second order vector differential inclusions. First we show the existence of extremal solutions of the periodic problem (i.e. solutions moving through the extreme points of the multifunction). Then for the Dirichlet problem we show that the extremal solutions are dense in the C 1 ( T , R N ) -norm in the set of solutions of the “convex” problem (relaxation theorem).

Currently displaying 641 – 660 of 1972