An estimate for the Novak number of a hyperspace with the Vietoris topology is given. As a consequence it is shown that this cardinal function can decrease passing from a space to its hyperspace.
@article{118541,
author = {Angelo Bella and Camillo Costantini},
title = {On the Novak number of a hyperspace},
journal = {Commentationes Mathematicae Universitatis Carolinae},
volume = {33},
year = {1992},
pages = {695-698},
zbl = {0782.54008},
mrnumber = {1240191},
language = {en},
url = {http://dml.mathdoc.fr/item/118541}
}
Bella, Angelo; Costantini, Camillo. On the Novak number of a hyperspace. Commentationes Mathematicae Universitatis Carolinae, Tome 33 (1992) pp. 695-698. http://gdmltest.u-ga.fr/item/118541/
The space of ultrafilters on $N$ covered by nowhere dense sets, Fund. Math. 110 n.1 (1980), 11-24. (1980) | MR 0600576 | Zbl 0568.54004
Some remarks on the Novak number, Proceedings of the 6th Prague Topological Symposium - General Topology and its Relations to Modern Analysis and Algebra VI - Z. Frolík ed., Heldermann Verlag, Berlin (1988), pp. 43-48. | MR 0952589 | Zbl 0634.54004
Some cardinality properties of a hyperspace with the locally finite topology, Proc. Amer. Math. Soc. 104 n. 4 (1988), 1274-1278. (1988) | MR 0969059 | Zbl 0692.54002
Set Theory. An introduction to independence proofs, North Holland Pub. Co., 1980. | MR 0597342 | Zbl 0534.03026
Topologies on spaces of subsets, Trans. Amer. Math. Soc. 71 (1951), 152-182. (1951) | MR 0042109 | Zbl 0043.37902
Spaces of high power, Fund. Math. 37 (1950), 125-136. (1950) | MR 0040643 | Zbl 0041.09705