Minimizing convex functions by continuous descent methods.
Mittag-Leffler methods in analysis.
In this survey we present two Mittag-Leffler lemmas and several applications to topics as varied as the delta-equation, Fréchet algebras, inductive limits of Banach spaces and quasi-normable Fréchet spaces.
Multi-valued contraction mappings in complete metric spaces
Multivalued generalized contractions and fixed point theorems
New fixed point theorems for mappings satisfying a generalized weakly contractive condition with weaker control functions
The purpose of this paper is to derive new common fixed point theorems for a pair of mappings satisfying a more general weakly contractive condition with weaker control functions in a complete metric space. Applications to new fixed point results with conditions of integral type are also given. We furnish an example to demonstrate that these results improve the previously existing ones.
Non-abelian group structure on the Urysohn universal space
We prove that there exists a non-abelian group structure on the Urysohn universal metric space. More precisely, we introduce a variant of the Graev metric that enables us to construct a free group with countably many generators equipped with a two-sided invariant metric that is isometric to the rational Urysohn space. We list several related open problems.
Non-locally compact Polish groups and two-sided translates of open sets
This paper is devoted to the following question. Suppose that a Polish group G has the property that some non-empty open subset U is covered by finitely many two-sided translates of every other non-empty open subset of G. Is then G necessarily locally compact? Polish groups which do not have the above property are called strongly non-locally compact. We characterize strongly non-locally compact Polish subgroups of in terms of group actions, and prove that certain natural classes of non-locally...
Non-separable analytic spaces and measurability
Non-Unique Fixed Points In L-Spaces
Non-unique fixed points in L-spaces.
On a dense -diagonal.
On a modified game of Sierpiński
On a problem of Banach
On completeness of quasi-pseudometric spaces.
On complexity of metric spaces
On coupled random fixed point results in partially ordered metric spaces
On existence and uniqueness of Chebyshev center of bounded set in a special geodesic space.
On half-completion and bicompletion of quasi-metric spaces
We characterize the quasi-metric spaces which have a quasi-metric half-completion and deduce that each paracompact co-stable quasi-metric space having a quasi-metric half-completion is metrizable. We also characterize the quasi-metric spaces whose bicompletion is quasi-metric and it is shown that the bicompletion of each quasi-metric compatible with a quasi-metrizable space is quasi-metric if and only if is finite.
On indecomposability and composants of chaotic continua
A homeomorphism f:X → X of a compactum X with metric d is expansive if there is c > 0 such that if x,y ∈ X and x ≠ y, then there is an integer n ∈ ℤ such that . A homeomorphism f: X → X is continuum-wise expansive if there is c > 0 such that if A is a nondegenerate subcontinuum of X, then there is an integer n ∈ ℤ such that . Clearly, every expansive homeomorphism is continuum-wise expansive, but the converse assertion is not true. In [6], we defined the notion of chaotic continua of homeomorphisms...
On metrizable abelian groups with a completeness-type property