Zobrazeno 1 - 5
of 5
pro vyhledávání: '"Hru����k, Michael"'
We study ultrafilters on countable sets and reaping families which are indestructible by Sacks forcing. We deal with the combinatorial characterization of such families and we prove that every reaping family of size smaller than the continuum is Sack
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https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d84a2179187323d4ebc39d9e65ff3fa0
http://arxiv.org/abs/2110.07945
http://arxiv.org/abs/2110.07945
We investigate the Tukey order in the class of $F_��$ ideals of subsets of $��$. We show that no nontrivial $F_��$ ideal is Tukey below a $G_��$ ideal of compact sets. We introduce the notions of flat ideals and gradually flat ideals.
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An almost disjoint family $\mathcal A$ of subsets of $\mathbb N$ is said to be $\mathbb R$-embeddable if there is a function $f:\mathbb N\rightarrow \mathbb R$ such that the sets $f[A]$ are ranges of real sequences converging to distinct reals for di
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https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b36d828ba274e9f58612b4dd936b8375
http://arxiv.org/abs/1901.00517
http://arxiv.org/abs/1901.00517
We show that all sufficiently nice $��$-sets are countable dense homogeneous ($\mathsf{CDH}$). From this fact we conclude that for every uncountable cardinal $��\le \mathfrak{b}$ there is a countable dense homogeneous metric space of size $
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Autor:
Greb��k, Jan, Hru����k, Michael
Answering a question of the second listed author we show that there is no tall Borel ideal minimal among all tall Borel ideals in the Kat��tov order.
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https://explore.openaire.eu/search/publication?articleId=doi_________::26bde0643ac219764363fc90bf4225ba