Zobrazeno 1 - 10
of 108
pro vyhledávání: '"Yan-Kui Song"'
Autor:
Wei-Feng Xuan, Yan-Kui Song
Publikováno v:
Mathematica Bohemica, Vol 144, Iss 2, Pp 113-123 (2019)
We study relationships between separability with other properties in semi-stratifiable spaces. Especially, we prove the following statements: (1) If $X$ is a semi-stratifiable space, then $X$ is separable if and only if $X$ is $DC(ømega_1)$; (2) If
Externí odkaz:
https://doaj.org/article/f2cc79951685420b9fc2eb45d36a6b5b
Autor:
Yan-Kui Song
Publikováno v:
Applied General Topology, Vol 10, Iss 1, Pp 13-20 (2009)
A space X is discretely absolutely star-Lindelöf if for every open cover U of X and every dense subset D of X, there exists a countable subset F of D such that F is discrete closed in X and St(F, U) = X, where St(F, U) = S{U ∈ U : U ∩F 6= Ø}. W
Externí odkaz:
https://doaj.org/article/4481dc4b91b742ee849826d0621b9f77
Autor:
Yan-Kui Song
Publikováno v:
Applied General Topology, Vol 9, Iss 2, Pp 293-299 (2008)
A space X is σ-starcompact if for every open cover U of X, there exists a σ-compact subset C of X such that St(C, U) = X. We investigate the relations between σ-starcompact spaces and other related spaces, and also study topological properties of
Externí odkaz:
https://doaj.org/article/8447071051604d0db5609c3d6a74e9c6
Autor:
Yan-Kui Song
Publikováno v:
Applied General Topology, Vol 8, Iss 2, Pp 249-258 (2007)
We introduce two new notions of topological spaces called a countably starcompact space and a countably absolutely countably compact (= countably acc) space. We clarify the relations between these spaces and other related spaces and investigate topol
Externí odkaz:
https://doaj.org/article/015ffb45468a4b2f821ec14ad1c23ccc
Autor:
Yan-Kui Song
Publikováno v:
Applied General Topology, Vol 7, Iss 1, Pp 131-138 (2006)
A space X has the property (wa) (or is a space with the property (wa)) if for every open cover U of X and every dense subspace D of X, there exists a discrete subspace F C D such that St(F, U) = X. In this paper, we give an example of a Tychonoff spa
Externí odkaz:
https://doaj.org/article/c32493afe4b64137891975e2bf453704
Autor:
Yan-Kui Song1 songyankui@njnu.edu.cn, Wei-Feng Xuan2 wfxuan@nau.edu.cn
Publikováno v:
Matematicki Vesnik. Dec2023, Vol. 75 Issue 4, p296-302. 7p.
Publikováno v:
International Journal of Control, Automation and Systems. 21:975-992
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ce6dff3fff08c9590f978a37e5a4413d
https://doi.org/10.1007/s12555-021-0629-4
https://doi.org/10.1007/s12555-021-0629-4
Autor:
Yan-Kui Song, Wei-Feng Xuan
Publikováno v:
Quaestiones Mathematicae; Vol. 46 No. 1 (2023); 73-83
Let P be a topological property. A space X is said to be star P if whenever U is an open cover of X, there exists a subspace A ⊆ X with property P such that X = St(A,𝒰), where St(A,𝒰) = ⋃ {U ∈ 𝒰 : U ∩ A ≠ ∅}. In this paper, we in
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f06235121c37befd447c45ed8ecf8b38
https://www.ajol.info/index.php/qm/article/view/243025
https://www.ajol.info/index.php/qm/article/view/243025
Autor:
Wei-Feng Xuan1 wfxuan@nau.edu.cn, Yan-Kui Song2 songyankui@njnu.edu.cn, Wei-Xue Shi3 wxshi@nju.edu.cn
Publikováno v:
Bulletin of the Belgian Mathematical Society - Simon Stevin. May2020, Vol. 27 Issue 1, p61-69. 9p.
Autor:
Yan-Kui Song, Wei-Feng Xuan
Publikováno v:
Studia Scientiarum Mathematicarum Hungarica. 57:139-146
In this paper, we prove that if X is a space with a regular Gδ-diagonal and X2 is star Lindelöf then the cardinality of X is at most 2c. We also prove that if X is a star Lindelöf space with a symmetric g-function such that {g2(n, x): n ∈ ω} =
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5cbca4797bf3a1e0da4d5591a0c72108
https://doi.org/10.1556/012.2020.57.2.1462
https://doi.org/10.1556/012.2020.57.2.1462