A combinatorial property of Fréchet iterated filters

Autor:	Gabriel Debs, Jean Saint Raymond
Rok vydání:	2012
Předmět:	Combinatorics Discrete mathematics Fréchet filter Intersection Baire classes Iterated function Fubini's theorem Product (mathematics) Geometry and Topology Filter (mathematics) Borel filters Borel functions Mathematics
Zdroj:	Topology and its Applications. 159:2205-2227
ISSN:	0166-8641
DOI:	10.1016/j.topol.2012.03.004
Popis:	For all m ⩾ 1 let N m be the filter on ω m obtained from the Frechet filter on ω by iterating the Fubini product operation. One easily checks that N m is a Σ 2 m 0 subset of P ( ω m ) and the main result of this work states that in any Π 2 m 0 subset of P ( ω m ) containing N m one can find m + 1 elements with empty intersection.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cd116511d7df6b7824ad8458608d5d75 https://doi.org/10.1016/j.topol.2012.03.004 Zobrazit plný text záznamu Full Text from ScienceDirect