Characterizations of spreading models of l 1

Persephone Kiriakouli

Commentationes Mathematicae Universitatis Carolinae (2000)

  • Volume: 41, Issue: 1, page 79-95
  • ISSN: 0010-2628

Abstract

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Rosenthal in [11] proved that if ( f k ) is a uniformly bounded sequence of real-valued functions which has no pointwise converging subsequence then ( f k ) has a subsequence which is equivalent to the unit basis of l 1 in the supremum norm. Kechris and Louveau in [6] classified the pointwise convergent sequences of continuous real-valued functions, which are defined on a compact metric space, by the aid of a countable ordinal index “ γ ”. In this paper we prove some local analogues of the above Rosenthal ’s theorem (spreading models of l 1 ) for a uniformly bounded and pointwise convergent sequence ( f k ) of continuous real-valued functions on a compact metric space for which there exists a countable ordinal ξ such that γ ( ( f n k ) ) > ω ξ for every strictly increasing sequence ( n k ) of natural numbers. Also we obtain a characterization of some subclasses of Baire-1 functions by the aid of spreading models of l 1 .

How to cite

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Kiriakouli, Persephone. "Characterizations of spreading models of $l^1$." Commentationes Mathematicae Universitatis Carolinae 41.1 (2000): 79-95. <http://eudml.org/doc/248583>.

@article{Kiriakouli2000,
abstract = {Rosenthal in [11] proved that if $(f_\{k\})$ is a uniformly bounded sequence of real-valued functions which has no pointwise converging subsequence then $(f_\{k\})$ has a subsequence which is equivalent to the unit basis of $l^\{1\}$ in the supremum norm. Kechris and Louveau in [6] classified the pointwise convergent sequences of continuous real-valued functions, which are defined on a compact metric space, by the aid of a countable ordinal index “$\gamma $”. In this paper we prove some local analogues of the above Rosenthal ’s theorem (spreading models of $l^\{1\}$) for a uniformly bounded and pointwise convergent sequence $(f_\{k\})$ of continuous real-valued functions on a compact metric space for which there exists a countable ordinal $\xi $ such that $\gamma ((f_\{n_\{k\}\}))> \omega ^\{\xi \}$ for every strictly increasing sequence $(n_\{k\})$ of natural numbers. Also we obtain a characterization of some subclasses of Baire-1 functions by the aid of spreading models of $l^\{1\}$.},
author = {Kiriakouli, Persephone},
journal = {Commentationes Mathematicae Universitatis Carolinae},
keywords = {uniformly bounded sequences of continuous real-valued functions; convergence index; spreading models of $l^\{1\}$; Baire-1 functions; spreading model; pointwise convergent subsequence; unit vector basis of ; generalized Schreier family; convergence index},
language = {eng},
number = {1},
pages = {79-95},
publisher = {Charles University in Prague, Faculty of Mathematics and Physics},
title = {Characterizations of spreading models of $l^1$},
url = {http://eudml.org/doc/248583},
volume = {41},
year = {2000},
}

TY - JOUR
AU - Kiriakouli, Persephone
TI - Characterizations of spreading models of $l^1$
JO - Commentationes Mathematicae Universitatis Carolinae
PY - 2000
PB - Charles University in Prague, Faculty of Mathematics and Physics
VL - 41
IS - 1
SP - 79
EP - 95
AB - Rosenthal in [11] proved that if $(f_{k})$ is a uniformly bounded sequence of real-valued functions which has no pointwise converging subsequence then $(f_{k})$ has a subsequence which is equivalent to the unit basis of $l^{1}$ in the supremum norm. Kechris and Louveau in [6] classified the pointwise convergent sequences of continuous real-valued functions, which are defined on a compact metric space, by the aid of a countable ordinal index “$\gamma $”. In this paper we prove some local analogues of the above Rosenthal ’s theorem (spreading models of $l^{1}$) for a uniformly bounded and pointwise convergent sequence $(f_{k})$ of continuous real-valued functions on a compact metric space for which there exists a countable ordinal $\xi $ such that $\gamma ((f_{n_{k}}))> \omega ^{\xi }$ for every strictly increasing sequence $(n_{k})$ of natural numbers. Also we obtain a characterization of some subclasses of Baire-1 functions by the aid of spreading models of $l^{1}$.
LA - eng
KW - uniformly bounded sequences of continuous real-valued functions; convergence index; spreading models of $l^{1}$; Baire-1 functions; spreading model; pointwise convergent subsequence; unit vector basis of ; generalized Schreier family; convergence index
UR - http://eudml.org/doc/248583
ER -

References

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  6. Kechris A.S., Louveau A., A classification of Baire class 1 functions, Trans. Amer. Math. Soc. 318 (1990), 209-236. (1990) Zbl0692.03031MR0946424
  7. Kiriakouli P., Namioka spaces, Baire-1 functions, Combinatorial principles of the type of Ramsey and their applications in Banach spaces theory (in Greek), Doctoral Dissertation, Athens Univ., 1994. 
  8. Kiriakouli P., Classifications and characterizations of Baire-1 functions, Comment. Math. Univ. Carolinae 39.4 (1998), 733-748. (1998) MR1715462
  9. Kiriakouli P., On combinatorial theorems with applications to Banach spaces theory, preprint, 1994. 
  10. Mercourakis S., Negrepontis S., Banach spaces and topology II, Recent Progress in General Topology, M. Hušek and J. van Mill, eds., Elsevier Science Publishers B.V., 1992, pp.495-536. Zbl0832.46005
  11. Rosenthal H.P., A characterization of Banach spaces containing l 1 , Proc. Nat. Acad. Sci. U.S.A. 71 (1974), 2411-2413. (1974) MR0358307

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