Zobrazeno 1 - 10
of 49
pro vyhledávání: '"Yukinobu Yajima"'
Autor:
Yasushi Hirata, Yukinobu Yajima
Publikováno v:
Topology and its Applications. 315:108157
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::cd65e49a10f653d37f7032943d7ab134
https://doi.org/10.1016/j.topol.2022.108157
https://doi.org/10.1016/j.topol.2022.108157
Publikováno v:
Topology and its Applications. 307:107946
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::1b6e7f8a5fc9075217c4f1107ca85d92
https://doi.org/10.1016/j.topol.2021.107946
https://doi.org/10.1016/j.topol.2021.107946
Autor:
Yasushi Hirata, Yukinobu Yajima
Publikováno v:
Topology and its Applications. 283:107350
Let X = ∏ α ∈ ω 1 X α be a product of ω 1 many separable metric spaces. It is proved that every C ⁎ -embedded subset in X is C-embedded in X under a certain set-theoretic assumption. Combining a result of E. Pol and R. Pol for N 2 ω , it i
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f2b29340115770c5b3558bc1d7c4237e
https://doi.org/10.1016/j.topol.2020.107350
https://doi.org/10.1016/j.topol.2020.107350
Autor:
Yukinobu Yajima, Yasushi Hirata
Publikováno v:
Topology and its Applications. 282:107325
Let A and B be two subspaces of an ordinal. It is proved that the product A × B is countably paracompact if and only if for every regular uncountable cardinal κ and for every closed rectangle A ′ × B ′ in A × B , either A ′ or B ′ contain
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::b08a3cce59f229742038b494824134c8
https://doi.org/10.1016/j.topol.2020.107325
https://doi.org/10.1016/j.topol.2020.107325
Autor:
Yasushi Hirata, Yukinobu Yajima
Publikováno v:
Topology and its Applications. 196:1033-1059
As separation of diagonal, we study when monotone normality implies Δ -paracompactness or Δ -normality. For that, it is proved that every monotonically normal space is Δ -paracompact if the projection of its square is closed. Moreover, it is prove
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::a40ecf8687258d9ada702910ab3bf7f0
https://doi.org/10.1016/j.topol.2015.05.027
https://doi.org/10.1016/j.topol.2015.05.027
Autor:
Yukinobu Yajima, Yasushi Hirata
Publikováno v:
Topology and its Applications. 195:297-311
We first point out that the product of a subparacompact D C -like space and a subparacompact D -space is a D -space. As a main result, we use elementary submodels to prove that any countable product of subparacompact D C -like spaces is a D -space. M
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3e2b7100c6bb169b11d80b8fc3041026
https://doi.org/10.1016/j.topol.2015.09.036
https://doi.org/10.1016/j.topol.2015.09.036
Publikováno v:
Topology and its Applications. 164:45-86
We give several characterizations of normality, orthocompactness and rectangularity for products of monotonically normal spaces and various special factors in terms of some neighborhood properties of the factors. Such a special factor is a compact fa
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f3417aa5001bae7923cf29cd244e03d4
https://doi.org/10.1016/j.topol.2013.12.006
https://doi.org/10.1016/j.topol.2013.12.006
Autor:
Yukinobu Yajima
Publikováno v:
Topology and its Applications. 158(15):2085-2089
Let S be the class of all spaces, each of which is homeomorphic to a stationary subset of a regular uncountable cardinal (depending on the space). In this paper, we prove the following result: The product X × C of a monotonically normal space X and
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3ed932ab48993b505a9d5f1f3fa40afb
Autor:
Yukinobu Yajima
Publikováno v:
Topology and its Applications. 157(8):1569-1592
Throughout this paper, we consider the following two problems: (A) When does a rectangular normal cover of a product X × Y (or an infinite product ∏ λ ∈ Λ X λ ) have a σ -locally finite rectangular cozero refinement? (B) What kind of a refin
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::02f11e378608569d25fd52af85c95c7b
Autor:
Yukinobu Yajima, Nobuyuki Kemoto
Publikováno v:
Topology and its Applications. 156(7):1348-1354
This paper deals with a question which is stated by quite simple definitions. A sequence { x n } in a space X is called a β-sequence if every subsequence of it has a cluster point in X . The closure of the sequence { x n } means the closure of { x n
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::eb3d07bd32fdc38899020a046c654b34