Common coupled fixed points of generalized contractive mappings in partially ordered metric spacesPositivity - Tập 17 - Trang 1021-1041 - 2013
Mujahid Abbas, Talat Nazir, Stojan Radenović
In this paper, we introduce the concept of a
$$w^{*}$$
-compatible mappings to obtain coupled coincidence point and coupled common fixed points of nonlinear contractive mappings in partially ordered metric spaces. Our results generalize, extend, unify, enrich and complement various comparable results in t...... hiện toàn bộ
On the Riemann-Hilbert factorization problem for positive definite functionsPositivity - Tập 20 - Trang 743-754 - 2015
Dan Kučerovský, Amir T. P. Najafabadi, Aydin Sarraf
We give several general theorems concerning positive definite solutions of Riemann-Hilbert problems on the real line. Furthermore, as an example, we apply our theory to the characteristic function of a class of Lévy processes and we find the distribution of their extrema at a given stopping time.
Function spaces arising from kernel operatorsPositivity - Tập 14 - Trang 637-653 - 2010
Guillermo P. Curbera, Werner J. Ricker
Given a probability space (Ω, μ) and a rearrangement invariant space X on [0,1], in certain situations inequalities for spaces of
$${\mathbb {R}}$$
-valued functions on Ω are equivalent to the boundedness of an associated operator T
K
: L
...... hiện toàn bộ
On a tensor-analogue of the Schur productPositivity - Tập 20 - Trang 621-624 - 2015
K. Sumesh, V. S. Sunder
We consider the tensorial Schur product
$$R \circ ^\otimes S = [r_{ij} \otimes s_{ij}]$$
for
$$R \in M_n(\mathcal {A}), S\in M_n(\mathcal {B}),...... hiện toàn bộ