Results 21 to 30 of about 220 (84)

Periodic orbits of continuous and discontinuous piecewise linear differential systems via first integrals [PDF]

open access: yes, 2017
Agraïments: The first author is partially supported by FEDER-UNAB-10-4E-378 and a CAPES grant 88881.
Llibre, Jaume, Teixeira, Marco Antonio
core   +2 more sources

Existence problems for homoclinic solutions

open access: yesAbstract and Applied Analysis, Volume 7, Issue 1, Page 1-27, 2002., 2002
The problem x˙=f(t,x), x(−∞)=x(+∞), where x(±∞) : = limt→±∞x(t) ∈ ℝn, is considered. Some existence results for this problem are established using the fixed point method and topological degree theory.
Cezar Avramescu
wiley   +1 more source

High Multiplicity and Chaos for an Indefinite Problem Arising from Genetic Models

open access: yesAdvanced Nonlinear Studies, 2020
We deal with the periodic boundary value problem associated with the parameter-dependent second-order nonlinear differential ...
Boscaggin Alberto   +2 more
doaj   +1 more source

On coincidence index for multivalued perturbations of nonlinear Fredholm maps and some applications

open access: yesAbstract and Applied Analysis, Volume 7, Issue 6, Page 295-322, 2002., 2002
We define a nonoriented coincidence index for a compact, fundamentally restrictible, and condensing multivalued perturbations of a map which is nonlinear Fredholm of nonnegative index on the set of coincidence points. As an application, we consider an optimal controllability problem for a system governed by a second‐order integro‐differential equation.
Valeri Obukhovskii   +2 more
wiley   +1 more source

Global behavior of positive solutions for some semipositone fourth-order problems

open access: yesAdvances in Difference Equations, 2018
In this paper, we study the global behavior of positive solutions of fourth-order boundary value problems {u′′′′=λf(x,u),x∈(0,1),u(0)=u(1)=u″(0)=u″(1)=0, $$ \textstyle\begin{cases} u''''=\lambda f(x,u), \quad x\in (0,1), \\ u(0)=u(1)=u''(0)=u''(1)=0 ...
Dongliang Yan, Ruyun Ma
doaj   +1 more source

Topological degree and application to a parabolic variational inequality problem

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 25, Issue 4, Page 273-287, 2001., 2001
We are interested in constructing a topological degree for operators of the form F = L + A + S, where L is a linear densely defined maximal monotone map, A is a bounded maximal monotone operators, and S is a bounded demicontinuous map of class (S+) with respect to the domain of L.
A. Addou, B. Mermri
wiley   +1 more source

On the solvability of a system of wave and beam equations

open access: yesAbstract and Applied Analysis, Volume 6, Issue 4, Page 215-228, 2001., 2001
We prove new existence results for linearly coupled system of wave and beam equations. The main concept is the matrix spectrum which is a natural extension of standard definition. Using invariant subspaces together with degree theoretic argument we obtain information about the range of the abstract operator.
Juha Berkovits
wiley   +1 more source

Maximal elements and equilibria of generalized games for 𝒰‐majorized and condensing correspondences

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 22, Issue 1, Page 179-189, 1999., 1999
In this paper, we first give an existence theorem of maximal elements for a new type of preference correspondences which are 𝒰‐majorized. Then some existence theorems for compact (resp., non‐compact) qualitative games and generalized games in which the constraint or preference correspondences are 𝒰‐majorized (resp., Ψ‐condensing) are obtained in ...
George Xian-Zhi Yuan, E. Tarafdar
wiley   +1 more source

On the degree theory for densely defined mappings of class (S+)L

open access: yesAbstract and Applied Analysis, Volume 4, Issue 3, Page 141-152, 1999., 1999
We introduce a new construction of topological degree for densely defined mappings of monotone type. We also study the structure of the classes of mappings involved. Using the basic properties of the degree, we prove some abstract existence results that can be applied to elliptic problems.
Juha Berkovits
wiley   +1 more source

Properness and Topological Degree for Nonlocal Reaction-Diffusion Operators [PDF]

open access: yes, 2011
International audienceThe paper is devoted to integro-differential operators, which correspond to non-local reaction-diffusion equations considered on the whole axis. Their Fredholm property and properness will be proved.
Apreutesei, Narcisa, Volpert, Vitaly
core   +4 more sources

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