Complexity of weakly null sequences

Alspach, D; Argyros, S

dc.contributor.author	Alspach, D	en
dc.contributor.author	Argyros, S	en
dc.date.accessioned	2014-03-01T01:41:03Z
dc.date.available	2014-03-01T01:41:03Z
dc.date.issued	1992	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/23342
dc.relation.uri	http://arxiv.org/abs/math/9202204	en
dc.subject	Indexation	en
dc.title	Complexity of weakly null sequences	en
heal.type	journalArticle	en
heal.publicationDate	1992	en
heal.abstract	We introduce an ordinal index which measures the complexity of a weakly nullsequence, and show that a construction due to J. Schreier can be iterated toproduce for each alpha < omega_1, a weakly null sequence (x^{alpha}_n)_n inC(omega^{omega^{alpha}})) with complexity alpha. As in the Schreier exampleeach of these is a sequence of indicator functions which is a	en