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Mostrando ítems 1-10 de 19
Artículo
On stationary points of nonexpansive set-valued mappings
(Springer, 2015-12)
In this paper we deal with stationary points (also known as endpoints) of nonexpansive set-valued mappings and show that the existence of such points under certain conditions follows as a consequence of the existence of ...
Artículo
Mutually nearest and farthest points of sets and the Drop Theorem in geodesic spaces
(Springer, 2012-02)
Let A and X be nonempty, bounded and closed subsets of a geodesic metric space (E, d). The minimization (resp. maximization) problem denoted by min(A, X) (resp. max(A, X)) consists in finding (a0,x0)∈A×X(a0,x0)∈A×X such ...
Artículo
Geodesic Ptolemy spaces and fixed points
(Elsevier, 2011-01-01)
We prove that geodesic Ptolemy spaces with a continuous midpoint map are strictly convex. Moreover, we show that geodesic Ptolemy spaces with a uniformly continuous midpoint map are reflexive and that in such a setting ...
Artículo
Weakly coercive mappings sharing a value
(Academy of Sciences of Czech Republic, Mathematical Institute, 2011)
Some sufficient conditions are provided that guarantee that the difference of a compact mapping and a proper mapping defined between any two Banach spaces over K has at least one zero. When conditions are strengthened, ...
Artículo
The fixed point property and unbounded sets in CAT(0) spaces
(Elsevier, 2013-12-15)
In this work we study the fixed point property for nonexpansive self-mappings defined on convex and closed subsets of a CAT(0) space. We will show that a positive answer to this problem is very much linked with the Euclidean ...
Artículo
Some examples of matrix-valued orthogonal functions having a differential and an integral operator as eigenfunctions
(Elsevier, 2011-05)
The aim of this paper is to show some examples of matrix-valued orthogonal functions on the real line which are simultaneously eigenfunctions of a second-order differential operator of Schrödinger type and an integral ...
Artículo
A proof-theoretic bound extraction theorem for CAT(κ)-spaces
(Springer, 2017-06)
Starting in 2005, general logical metatheorems have been developed that guarantee the extractability of uniform effective bounds from large classes of proofs of theorems that involve abstract metric structures X. In this ...
Artículo
A fixed point theorem for weakly Zamfirescu mappings
(Elsevier, 2011-03-01)
In [13] T. Zamfirescu, Fixed point theorems in metric spaces, Arch. Math. 23 (1972), 292–298. Zamfirescu gave a fixed point theorem that generalizes the classical fixed point theorems by Banach, Kannan and Chatterjea. In ...
Artículo
Density of the set of renormings in c0 without asymptotically isometric copies of c0 and failing to have the fixed point property
(Casa Cărţii de Ştiinţă Cluj-Napoca, 2013)
It is proved that the family of all equivalent norms in c0 without asymptotically isometric copies of c0 and failing to have the fixed point property is dense in the set of all renormings of c0.
Artículo
Spectral properties of certain tridiagonal matrices
(Elsevier, 2012-02-01)
We study spectral properties of irreducible tridiagonal k−Toeplitz matrices and certain matrices which arise as perturbations of them.