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TOPOLOGICAL METHODS IN NONLINEAR ANALYSIS
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Vol. 36, No. 2 December 2010 |
TABLE OF CONTENTS
Title and Author(s) |
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Rigorous numerics for dissipative PDEs III. An effective algorithm for rigorous integration of dissipative PDEs
Piotr Zgliczyński
ABSTRACT.
We describe a Lohner-type algorithm for rigorous integration
of dissipative PDEs. Using it for the Kuramoto-Sivashinsky PDE
on the line with odd and periodic boundary conditions
we give a computer assisted proof the existence of
multiple periodic orbits.
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197
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Positive solutions for a class of nonlocal impulsive BVPs via fixed point index
Gennaro Infante, Paolamaria Pietramala and Miroslawa Zima
ABSTRACT.
We study the existence of positive solutions for
perturbed impulsive integral equations. Our setting is quite
general and covers a wide class of impulsive boundary value problems.
We also study other cases that can be treated in a similar manner. The
main ingredient in our theory is the classical fixed point index
theory for compact maps.
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263
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Existence and multiplicity of nontrivial solutions for semilinear elliptic Dirichlet problems across resonace
Xianojun Chang and Yong Li
ABSTRACT.
With the
linear growth of the nonlinearity and a new compactness condition
involving the asymptotic behavior of its potential at infinity, we
establish the existence and multiplicity results of nontrivial
solutions for semilinear elliptic Dirichlet problems. The
nonlinearity may cross multiple eigenvalues.
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285
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Eigenvalue criteria for existence of positive solutions of second-order, multi-point, $p$-Laplacian boundary value problems
Bryan P. Rynne
ABSTRACT.
In this paper we consider the existence and uniqueness of positive
solutions of the multi-point boundary value problem
(1) - (\phi_p(u')' + (a + g(x,u,u'))\phi_p(u) = 0 , \quad\text{a.e. on $(-1,1)$},
(2) u(\pm 1) = \sum^{m^\pm}_{i=1}\al^\pm_i u(\eta^\pm_i) ,
where $p>1$, $\phi_p(s) := |s|^{p-2} s$, $s \in \R$, $m^\pm \ge 1$ are integers,
and
\eta_i^\pm \in (-1,1),\quad
\al_i^\pm > 0,\quad i = 1,\dots,m^\pm, \quad
\sum^{m^\pm}_{i=1} \al_i^\pm < 1 .
Also,
$a \in L^1(-1,1),$
and
$g \colon [-1,1] \X \R^2 \to \R$ is Carath{\'e}odory,
with
(3) g(x,0,0) = 0, \quad x \in [-1,1].
Our criteria for existence of positive solutions of
(1), (2)
will be expressed in terms of the asymptotic behaviour of
$g(x,s,t)$, as $s \to \infty$,
and the principal eigenvalues of the
multi-point boundary value problem consisting of the equation
(4) -\phi_p (u')' + a \phi_p (u) = \la \phi_p (u) , \quad \text{on $(-1,1)$}.
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311
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Root problem for convenient maps
Marcio Colombo Fenille and Oziride Manzoli Neto
ABSTRACT.
In this paper we study when the minimal
number of roots of the so-called convenient maps from
two-dimensional CW complexes into closed surfaces is zero. We
present several necessary and sufficient conditions for such a map
to be root free. Among these conditions we have the existence of
specific liftings for the homomorphism induced by the map on the
fundamental groups, existence of the so-called mutation of a
specific homomorphism also induced by the map, and existence of
particular solutions of specific systems of equations on free groups
over specific subgroups.
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327
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On the spectral flow for paths of essentially hyperbolic bounded
operators on Banach spaces
Daniele Garrisi
ABSTRACT.
We give a definition of the spectral flow for paths of
bounded essentially hyperbolic operators on a Banach space. The spectral flow
induces a group homomorphism on the fundamental group of every connected
component of the space of essentially hyperbolic operators. We prove that this
homomorphism completes the exact homotopy sequence of a Serre fibration.
This allows us to characterise its kernel and image and to produce examples of
spaces where it is not injective or not surjective, unlike
what happens for Hilbert spaces. For a large class of paths, namely
the essentially splitting, the spectral flow of $ A $ coincides with
$ -\ind(F_A) $, the Fredholm index of the differential operator
$ F_A (u) = u' - A u $.
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353
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Structure of the fixed-point set of mapping with lipschitzian iterates
Jarosław Górnicki
ABSTRACT.
We prove, by asymptotic center techniques and some inequalities
in Banach spaces, that if $E$ is $p$-uniformly convex Banach space,
$C$ is a nonempty bounded closed convex
subset of $E$, and $T\colon C\rightarrow C$ has lipschitzian iterates
(with some restrictions), then the set of fixed-points is not only
connected but even a retract of $C$. The results presented in this
paper improve and extend some results in \cite{6}, \cite{8}.
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381
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