Zobrazeno 1 - 10
of 41
pro vyhledávání: '"Tsugunori Nogura"'
Autor:
Valentin Gutev, Tsugunori Nogura
Publikováno v:
Applied General Topology, Vol 5, Iss 1, Pp 71-78 (2004)
The theory of hyperspaces has attracted the attention of many mathematicians who have found a large variety of its applications during the last decades. The theory has taken also its natural course and has yielded lots of problems which, besides thei
Externí odkaz:
https://doaj.org/article/170960ac23b343d89e947f9a9356bd64
Autor:
Valentin Gutev, Tsugunori Nogura
Publikováno v:
Applied General Topology, Vol 2, Iss 2, Pp 205-218 (2001)
Every selection f for the family F2(X) of at most two-point subsets of a set X naturally defines an order-like relation on X by if and only . In the present paper we study the relationship between and the possible topologies T on X which realize the
Externí odkaz:
https://doaj.org/article/493f7ccacded431db1ecc277a09d6a89
Publikováno v:
Topology and its Applications. 230:490-505
We study properties of the pseudocompact spaces X with a weak selection, and we dedicate a particular attention to the weak selection topologies on X. In case when X is also locally compact, we obtain a convenient decomposition of X into a finite uni
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1c5528d8fb9fc21e75828c4528e24963
https://doi.org/10.1016/j.topol.2017.08.019
https://doi.org/10.1016/j.topol.2017.08.019
Publikováno v:
Topology and its Applications. 160:2465-2472
A weak selection on an infinite set X is a function σ : [ X ] 2 → X such that σ ( { x , y } ) ∈ { x , y } for each { x , y } ∈ [ X ] 2 . A weak selection on a space is said to be continuous if it is a continuous function with respect to the V
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::b93fa31687b83131aaf4dcffe2aa368e
https://doi.org/10.1016/j.topol.2013.07.040
https://doi.org/10.1016/j.topol.2013.07.040
Autor:
Valentin Gutev, Tsugunori Nogura
Publikováno v:
Topology and its Applications. 157(8):1249-1274
In 1951 Ernest Michael wrote a definitive seminal article on hyperspaces [E. Michael, Topologies on spaces of subsets, Trans. Amer. Math. Soc. 71 (1951) 152–182] raising a general question that became known as Michael's selection problem for hypers
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7b25e8533aaa2eedf6117649143323cd
Autor:
Tsugunori Nogura, Valentin Gutev
Publikováno v:
Topology and its Applications. 155:824-829
We demonstrate that for every n ω there exists a separable completely metrizable space X n which has a continuous selection for its Vietoris hyperspace of nonempty compact subsets, but dim ( X n ) = n . Related results and open problems are discusse
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6369c218361e25f5eef912cbfbdc437d
https://doi.org/10.1016/j.topol.2007.06.020
https://doi.org/10.1016/j.topol.2007.06.020
Publikováno v:
Journal of the Korean Mathematical Society. 44:845-854
In this paper we investigate relationships between closure-type and convergence-type properties of hyperspaces over a space X and covering properties of X.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0722efbcf6c57ebaab0555878a0fd5e6
https://doi.org/10.4134/jkms.2007.44.4.845
https://doi.org/10.4134/jkms.2007.44.4.845
Autor:
Valentin Gutev, Tsugunori Nogura
Publikováno v:
Topology and its Applications. 153:900-911
Every selection f : F 2 ( X ) → X for the family F 2 ( X ) of at most two-point subsets of a set X naturally defines an order-like relation ⪯ f on X by letting x ⪯ f y if and only if f ( { x , y } ) = x . In particular, it also defines a natura
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::13956fbef58390c9f6f1bcc89d980c8d
https://doi.org/10.1016/j.topol.2005.01.019
https://doi.org/10.1016/j.topol.2005.01.019
Autor:
Tsugunori Nogura, Valentin Gutev
Publikováno v:
Mathematika. 51:163-169
The present paper improves a result of [3] by showing that a space X is topologically well-orderable if and only if there exists a selection for F2(X) which is continuous with respect to the Fell topology on F2(X). In particular, this implies that F(
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::6a4ec92af156594ab14fed608fbb4f1b
https://doi.org/10.1112/s002557930001559x
https://doi.org/10.1112/s002557930001559x
Publikováno v:
Topology and its Applications. 144:133-145
In this paper, we study the countable compactness and pseudocompactness of the hyperspace 2X of a Hausdorff space X consisting of all nonempty closed subsets of X equipped with the Vietoris topology. Some open questions posed by Ginsburg in 1975 are
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b9857048aaf2e9b29028193587bbb3b2
https://doi.org/10.1016/j.topol.2004.05.001
https://doi.org/10.1016/j.topol.2004.05.001