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Separation properties for self-conformal sets

Yuan-Ling Ye (2002)

Studia Mathematica

For a one-to-one self-conformal contractive system w j j = 1 m on d with attractor K and conformality dimension α, Peres et al. showed that the open set condition and strong open set condition are both equivalent to 0 < α ( K ) < . We give a simple proof of this result as well as discuss some further properties related to the separation condition.

Sobre las isometrías de los grupos y anillos reticulados.

Josep Grané Manlleu (1980)

Stochastica

El contenido de este trabajo tiene un objetivo fundamental: el estudio, clasificación y caracterización de las isometrías de un grupo reticulado. Se introducen los conceptos de grupo de isometrías M(G) de un grupo reticulado G, grupo de simetrías homogéneas H(G) y traslaciones T(G). Se estudia primero el caso elemental de los grupos totalmente ordenados y utilizando luego las representaciones de los grupos (y f-anillos) en un producto de totalmente ordenados, se introduce el concepto de conjunto...

Some results on L Σ ( κ ) -spaces

Fidel Casarrubias Segura, Oleg Okunev, Paniagua C. G. Ramírez (2008)

Commentationes Mathematicae Universitatis Carolinae

We present several results related to L Σ ( κ ) -spaces where κ is a finite cardinal or ω ; we consider products and some constructions that lead from spaces of these classes to other spaces of similar classes.

Spaces with countable s n -networks

Ge Ying (2004)

Commentationes Mathematicae Universitatis Carolinae

In this paper, we prove that a space X is a sequentially-quotient π -image of a metric space if and only if X has a point-star s n -network consisting of c s * -covers. By this result, we prove that a space X is a sequentially-quotient π -image of a separable metric space if and only if X has a countable s n -network, if and only if X is a sequentially-quotient compact image of a separable metric space; this answers a question raised by Shou Lin affirmatively. We also obtain some results on spaces with countable...

Striped structures of stable and unstable sets of expansive homeomorphisms and a theorem of K. Kuratowski on independent sets

Hisao Kato (1993)

Fundamenta Mathematicae

We investigate striped structures of stable and unstable sets of expansive homeomorphisms and continuum-wise expansive homeomorphisms. The following theorem is proved: if f : X → X is an expansive homeomorphism of a compact metric space X with dim X > 0, then the decompositions W S ( x ) | x X and W ( u ) ( x ) | x X of X into stable and unstable sets of f respectively are uncountable, and moreover there is σ (= s or u) and ϱ > 0 such that there is a Cantor set C in X with the property that for each x ∈ C, W σ ( x ) contains a nondegenerate...

Strongly paracompact metrizable spaces

Valentin Gutev (2016)

Colloquium Mathematicae

Strongly paracompact metrizable spaces are characterized in terms of special S-maps onto metrizable non-Archimedean spaces. A similar characterization of strongly metrizable spaces is obtained as well. The approach is based on a sieve-construction of "metric"-continuous pseudo-sections of lower semicontinuous mappings.

The nonexistence of expansive homeomorphisms of chainable continua

Hisao Kato (1996)

Fundamenta Mathematicae

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 d ( f n ( x ) , f n ( y ) ) > c . In this paper, we prove that if a homeomorphism f:X → X of a continuum X can be lifted to an onto map h:P → P of the pseudo-arc P, then f is not expansive. As a corollary, we prove that there are no expansive homeomorphisms on chainable continua. This is an affirmative answer to one of Williams’ conjectures.

The solenoids are the only circle-like continua that admit expansive homeomorphisms

Christopher Mouron (2009)

Fundamenta Mathematicae

A homeomorphism h:X → X of a compactum X is expansive provided that for some fixed c > 0 and any distinct x, y ∈ X there exists an integer n, dependent only on x and y, such that d(hⁿ(x),hⁿ(y)) > c. It is shown that if X is a circle-like continuum that admits an expansive homeomorphism, then X is homeomorphic to a solenoid.

Currently displaying 161 – 180 of 198