Pełnotekstowe zasoby PLDML oraz innych baz dziedzinowych są już dostępne w nowej Bibliotece Nauki.
Zapraszamy na https://bibliotekanauki.pl
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 6

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available remote

On some properties of squares of Sierpiński sets

100%
Nowik A.
Colloquium Mathematicum
|
2004
|
tom 99
|
nr 2
221-229
EN
We investigate some geometrical properties of squares of special Sierpiński sets. In particular, we prove that (under CH) there exists a Sierpiński set S and a function p: S → S such that the images of the graph of this function under π'(⟨x,y⟩) = x - y and π''(⟨x,y⟩) = x + y are both Lusin sets.
2
Content available remote

Additive properties and uniformly completely Ramsey sets

100%
Nowik A.
Colloquium Mathematicum
|
1999
|
tom 82
|
nr 2
191-199
EN
We prove some properties of uniformly completely Ramsey null sets (for example, every hereditarily Menger set is uniformly completely Ramsey null).
3
Content available remote

Possibly there is no uniformly completely Ramsey null set of size $2^{ω}$

100%
Nowik A.
Colloquium Mathematicum
|
2002
|
tom 93
|
nr 2
251-258
EN
We show that under the axiom $CPA_{cube}$ there is no uniformly completely Ramsey null set of size $2^{ω}$. In particular, this holds in the iterated perfect set model. This answers a question of U. Darji.
4
Content available remote

On the structure of perfect sets in various topologies associated with tree forcings

64%
Nowik A., Reardon P.
Open Mathematics
|
2013
|
tom 11
|
nr 3
509-518
EN
We prove that the Ellentuck, Hechler and dual Ellentuck topologies are perfect isomorphic to one another. This shows that the structure of perfect sets in all these spaces is the same. We prove this by finding homeomorphic embeddings of one space into a perfect subset of another. We prove also that the space corresponding to eventually different forcing cannot contain a perfect subset homeomorphic to any of the spaces above.
5
Content available remote

The ideal (a) is not $G_δ$ generated

64%
Frankowska M., Nowik A.
Colloquium Mathematicum
|
2011
|
tom 125
|
nr 1
7-14
EN
We prove that the ideal (a) defined by the density topology is not $G_δ$ generated. This answers a question of Z. Grande and E. Strońska.
6
Content available remote

On nowhere weakly symmetric functions and functions with two-element range

51%
Ciesielski K., Muthuvel K., Nowik A.
Fundamenta Mathematicae
|
2001
|
tom 168
|
nr 2
119-130
EN
A function f: ℝ → {0,1} is weakly symmetric (resp. weakly symmetrically continuous) at x ∈ ℝ provided there is a sequence hₙ → 0 such that f(x+hₙ) = f(x-hₙ) = f(x) (resp. f(x+hₙ) = f(x-hₙ)) for every n. We characterize the sets S(f) of all points at which f fails to be weakly symmetrically continuous and show that f must be weakly symmetric at some x ∈ ℝ∖S(f). In particular, there is no f: ℝ → {0,1} which is nowhere weakly symmetric. It is also shown that if at each point x we ignore some countable set from which we can choose the sequence hₙ, then there exists a function f: ℝ → {0,1} which is nowhere weakly symmetric in this weaker sense if and only if the continuum hypothesis holds.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.