Temat: free subset - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: On a problem of Steve Kalikow
Autorzy:: Shelah, Saharon
Powiązania:: https://bibliotekanauki.pl/articles/1205000.pdf
Data publikacji:: 2000
Wydawca:: Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:: set theory
forcing
continuity
Kalikow
free subset
Opis:: The Kalikow problem for a pair (λ,κ) of cardinal numbers,λ > κ (in particular κ = 2) is whether we can map the family of ω-sequences from λ to the family of ω-sequences from κ in a very continuous manner. Namely, we demand that for η,ν ∈ ω we have: η, ν are almost equal if and only if their images are. We show consistency of the negative answer, e.g., for $ℵ_ω$ but we prove it for smaller cardinals. We indicate a close connection with the free subset property and its variants.
Źródło:: Fundamenta Mathematicae; 2000, 166, 1-2; 137-151
0016-2736
Pojawia się w:: Fundamenta Mathematicae
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: On quasi-p-bounded subsets
Autorzy:: Sanchis, M.
Tamariz-Mascarúa, A.
Powiązania:: https://bibliotekanauki.pl/articles/965880.pdf
Data publikacji:: 1999
Wydawca:: Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:: free ultrafilter
P-point
(quasi)-p-pseudocompact space
Rudin-Keisler pre-order
p-limit point
(quasi)-p-bounded subset
bounded subset
Opis:: The notion of quasi-p-boundedness for p ∈ $ω^*$ is introduced and investigated. We characterize quasi-p-pseudocompact subsets of β(ω) containing ω, and we show that the concepts of RK-compatible ultrafilter and P-point in $ω^*$ can be defined in terms of quasi-p-pseudocompactness. For p ∈ $ω^*$, we prove that a subset B of a space X is quasi-p-bounded in X if and only if B × $P_{RK}(p)$ is bounded in X × $P_{RK}(p)$, if and only if $cl_{β(X × P_{RK}(p))}(B× P_{RK}(p)) = cl_{βX} B × β(ω)$, where $P_{RK}(p)$ is the set of Rudin-Keisler predecessors of p.
Źródło:: Colloquium Mathematicum; 1999, 80, 2; 175-189
0010-1354
Pojawia się w:: Colloquium Mathematicum
Dostawca treści:: Biblioteka Nauki

Artykuł

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