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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 selections of multifunctions generating a continuous flow

Alberto Bressan, Graziano Crasta (1994)

Annales Polonici Mathematici

Let F : [ 0 , T ] × n 2 n be a continuous multifunction with compact, not necessarily convex values. In this paper, we prove that, if F satisfies the following Lipschitz Selection Property: (LSP) For every t,x, every y ∈ c̅o̅F(t,x) and ε > 0, there exists a Lipschitz selection ϕ of c̅o̅F, defined on a neighborhood of (t,x), with |ϕ(t,x)-y| < ε, then there exists a measurable selection f of ext F such that, for every x₀, the Cauchy problem ẋ(t) = f(t,x(t)), x(0) = x₀, has a unique Carathéodory solution, depending...

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).

Extremal Solutions for a Class of Functional Differential Equations

Ceppitelli, Rita, Faina, Loris (1997)

Serdica Mathematical Journal

We study, in Carathéodory assumptions, existence, continuation and continuous dependence of extremal solutions for an abstract and rather general class of hereditary differential equations. By some examples we prove that, unlike the nonfunctional case, solved Cauchy problems for hereditary differential equations may not have local extremal solutions.

Factorisation d'opérateurs différentiels à coefficients dans une extension liouvillienne d'un corps valué

Magali Bouffet (2002)

Annales de l’institut Fourier

On démontre ici un lemme de Hensel pour les opérateurs différentiels. On en déduit un théorème de factorisation pour des opérateurs différentiels à coefficients dans une extension liouvillienne transcendante d’un corps valué. On obtient en particulier un théorème de factorisation pour des opérateurs différentiels à coefficients dans une extension de ( ( z ) ) par un nombre fini d’exponentielles et de logarithmes algébriquement indépendants sur ( ( z ) ) .

Families of linear differential equations related to the second Painlevé equation

Marius van der Put (2011)

Banach Center Publications

This paper is a sequel to [vdP-Sa] and [vdP]. The two classes of differential modules (0,-,3/2) and (-,-,3), related to PII, are interpreted as fine moduli spaces. It is shown that these moduli spaces coincide with the Okamoto-Painlevé spaces for the given parameters. The geometry of the moduli spaces leads to a proof of the Painlevé property for PII in standard form and in the Flaschka-Newell form. The Bäcklund transformations, the rational solutions and the Riccati solutions for PII are derived...

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