The number of metrizable spaces
The omega limit sets of subsets in a metric space
In this paper, we discuss the properties of limit sets of subsets and attractors in a compact metric space. It is shown that the -limit set of is the limit point of the sequence in and also a quasi-attractor is the limit point of attractors with respect to the Hausdorff metric. It is shown that if a component of an attractor is not an attractor, then it must be a real quasi-attractor.
The one-point countable compactification of curve spaces and arc spaces
The one-point Lindelöfication of an uncountable discrete space can be surlindelöf
We prove that the one-point Lindelöfication of a discrete space of cardinality ω 1 is homeomorphic to a subspace of C p (X) for some hereditarily Lindelöf space X if the axiom [...] holds.
The open-cover topology on function spaces
The openness of induced maps on hyperspaces
The open-open topology for function spaces.
The operation of infimal convolution [Book]
The Order Aspect of the Fuzzy Real Line.
The order topology for function lattices and realcompactness.
The origins of the concept of dimension
The parabolic-parabolic Keller-Segel equation
I present in this note recent results on the uniqueness and stability for the parabolic-parabolic Keller-Segel equation on the plane, obtained in collaboration with S. Mischler in [11].
The partially ordered collection of regular ...-classes of S(X).
The partially ordered family of C M-homomorphisms.
The partially pre-ordered set of compactifications of Cp(X, Y)
In the set of compactifications of X we consider the partial pre-order defined by (W, h) ≤X (Z, g) if there is a continuous function f : Z ⇢ W, such that (f ∘ g)(x) = h(x) for every x ∈ X. Two elements (W, h) and (Z, g) of K(X) are equivalent, (W, h) ≡X (Z, g), if there is a homeomorphism h : W ! Z such that (f ∘ g)(x) = h(x) for every x ∈ X. We denote by K(X) the upper semilattice of classes of equivalence of compactifications of X defined by ≤X and ≡X. We analyze in this article K(Cp(X, Y)) where...
The Peano curves as limit of α-dense curves.
En este artículo presentamos una caracterización de las curvas de Peano como límite uniforme de sucesiones de curvas α-densas en el compacto que es llenado por la curva de Peano. Estas curvas α-densas deben tener densidades tendiendo a cero y sus funciones coordenadas deben de ser de variación tendiendo a infinito cuando α tiende a cero.
The periodic orbit structure of orientation preserving diffeomorphisms on D2 with topological entropy zero
The ping-pong game, geometric entropy and expansiveness for group actions on Peano continua having free dendrites
It is shown that each expansive group action on a Peano continuum having a free dendrite must have a ping-pong game, and has positive geometric entropy when the acting group is finitely generated. As a corollary, it is shown that each Peano continuum having a free dendrite admits no expansive nilpotent group actions.
The point of continuity property, neighbourhood assignments and filter convergences
We show that for some large classes of topological spaces X and any metric space (Z,d), the point of continuity property of any function f: X → (Z,d) is equivalent to the following condition: (*) For every ε > 0, there is a neighbourhood assignment of X such that d(f(x),f(y)) < ε whenever . We also give various descriptions of the filters ℱ on the integers ℕ for which (*) is satisfied by the ℱ-limit of any sequence of continuous functions from a topological space into a metric space.
The positive cone of a Banach lattice. Coincidence of topologies and metrizability
Let be a Banach lattice, and denote by its positive cone. The weak topology on is metrizable if and only if it coincides with the strong topology if and only if is Banach-lattice isomorphic to for a set . The weak topology on is metrizable if and only if is Banach-lattice isomorphic to a -space, where is a metrizable compact space.