A topological version of a combinatorial theorem of Katětov
A topology generated by eventually different functions
A topology on inequalities.
A Tychonoff non-normal space.
A Unified Theory of Perfect and Related Functions
A unified theory of weak separation properties.
A uniquely homogeneous space need not be a topological group
A universal metacompact developable -space of weight m
A universal planar completely regular continuum
We construct a universal planar completely regular continuum. This gives a positive answer to a problem posed by J. Krasinkiewicz (1986).
A universal separable metric locally finite-dimensional space
A variational problem for couples of functions and multifunctions with interaction between leaves
We discuss a variational problem defined on couples of functions that are constrained to take values into the 2-dimensional unit sphere. The energy functional contains, besides standard Dirichlet energies, a non-local interaction term that depends on the distance between the gradients of the two functions. Different gradients are preferred or penalized in this model, in dependence of the sign of the interaction term. In this paper we study the lower semicontinuity and the coercivity of the energy...
A Whitehead theorem in CG-shape
AANR spaces and absolute retracts for tree-like continua
Continua that are approximative absolute neighborhood retracts (AANR’s) are characterized as absolute terminal retracts, i.e., retracts of continua in which they are embedded as terminal subcontinua. This implies that any AANR continuum has a dense arc component, and that any ANR continuum is an absolute terminal retract. It is proved that each absolute retract for any of the classes of: tree-like continua, -dendroids, dendroids, arc-like continua and arc-like -dendroids is an approximative absolute...
About an example of a Banach space not weaky K-analytic.
About solutions of a functional equation.
About the inverse operations on the hyperespace of nonlinear monotone operators.
About the Maximum and the Minimum of Darboux Functions
About -covers and -networks on the Vietoris hyperspace
We study some generalized metric properties on the hyperspace of finite subsets of a space endowed with the Vietoris topology. We prove that has a point-star network consisting of (countable) -covers if and only if so does . Moreover, has a sequence of -covers with property which is a point-star network if and only if so does , where is one of the following properties: point-finite, point-countable, compact-finite, compact-countable, locally finite, locally countable. On the other...
Absolute end points and their mapping properties.
Absolute fixed point sets and AR-spaces