Universally Kuratowski–Ulam spaces
Fundamenta Mathematicae, Tome 165 (2000) no. 3, pp. 239-247
Cet article a éte moissonné depuis la source Institute of Mathematics Polish Academy of Sciences
We introduce the notions of Kuratowski-Ulam pairs of topological spaces and universally Kuratowski-Ulam space. A pair (X,Y) of topological spaces is called a Kuratowski-Ulam pair if the Kuratowski-Ulam Theorem holds in X× Y. A space Y is called a universally Kuratowski-Ulam (uK-U) space if (X,Y) is a Kuratowski-Ulam pair for every space X. Obviously, every meager in itself space is uK-U. Moreover, it is known that every space with a countable π-basis is uK-U. We prove the following: • every dyadic space (in fact, any continuous image of any product of separable metrizable spaces) is uK-U (so there are uK-U Baire spaces which do not have countable π-bases); • every Baire uK-U space is ccc.
Keywords:
Baire space, dyadic space, quasi-dyadic space, Kuratowski-Ulam Theorem, Kuratowski-Ulam pair, universally Kuratowski-Ulam space
Affiliations des auteurs :
David Fremlin 1 ; Tomasz Natkaniec 1 ; Ireneusz Recław 1
@article{10_4064_fm_165_3_239_247,
author = {David Fremlin and Tomasz Natkaniec and Ireneusz Rec{\l}aw},
title = {Universally {Kuratowski{\textendash}Ulam} spaces},
journal = {Fundamenta Mathematicae},
pages = {239--247},
year = {2000},
volume = {165},
number = {3},
doi = {10.4064/fm-165-3-239-247},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-165-3-239-247/}
}
TY - JOUR AU - David Fremlin AU - Tomasz Natkaniec AU - Ireneusz Recław TI - Universally Kuratowski–Ulam spaces JO - Fundamenta Mathematicae PY - 2000 SP - 239 EP - 247 VL - 165 IS - 3 UR - http://geodesic.mathdoc.fr/articles/10.4064/fm-165-3-239-247/ DO - 10.4064/fm-165-3-239-247 LA - en ID - 10_4064_fm_165_3_239_247 ER -
David Fremlin; Tomasz Natkaniec; Ireneusz Recław. Universally Kuratowski–Ulam spaces. Fundamenta Mathematicae, Tome 165 (2000) no. 3, pp. 239-247. doi: 10.4064/fm-165-3-239-247
Cité par Sources :