Order intervals in C ( K ) . Compactness, coincidence of topologies, metrizability

Zbigniew Lipecki

Commentationes Mathematicae Universitatis Carolinae (2022)

  • Volume: 62 63, Issue: 3, page 295-306
  • ISSN: 0010-2628

Abstract

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Let K be a compact space and let C ( K ) be the Banach lattice of real-valued continuous functions on K . We establish eleven conditions equivalent to the strong compactness of the order interval [ 0 , x ] in C ( K ) , including the following ones: (i) { x > 0 } consists of isolated points of K ; (ii) [ 0 , x ] is pointwise compact; (iii) [ 0 , x ] is weakly compact; (iv) the strong topology and that of pointwise convergence coincide on [ 0 , x ] ; (v) the strong and weak topologies coincide on [ 0 , x ] . Moreover, the weak topology and that of pointwise convergence coincide on [ 0 , x ] if and only if { x > 0 } is scattered. Finally, the weak topology on [ 0 , x ] is metrizable if and only if the topology of pointwise convergence on [ 0 , x ] is such if and only if { x > 0 } is countable.

How to cite

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Lipecki, Zbigniew. "Order intervals in $C(K)$. Compactness, coincidence of topologies, metrizability." Commentationes Mathematicae Universitatis Carolinae 62 63.3 (2022): 295-306. <http://eudml.org/doc/299039>.

@article{Lipecki2022,
abstract = {Let $K$ be a compact space and let $C(K)$ be the Banach lattice of real-valued continuous functions on $K$. We establish eleven conditions equivalent to the strong compactness of the order interval $[0,x]$ in $C(K)$, including the following ones: (i) $\lbrace x>0\rbrace $ consists of isolated points of $K$; (ii) $[0,x]$ is pointwise compact; (iii) $[0,x]$ is weakly compact; (iv) the strong topology and that of pointwise convergence coincide on $[0,x]$; (v) the strong and weak topologies coincide on $[0,x]$. Moreover, the weak topology and that of pointwise convergence coincide on $[0,x]$ if and only if $\lbrace x>0\rbrace $ is scattered. Finally, the weak topology on $[0,x]$ is metrizable if and only if the topology of pointwise convergence on $[0,x]$ is such if and only if $\lbrace x>0\rbrace $ is countable.},
author = {Lipecki, Zbigniew},
journal = {Commentationes Mathematicae Universitatis Carolinae},
keywords = {real linear lattice; order interval; locally solid; Banach lattice $C(K)$; strongly compact; weakly compact; pointwise compact; coincidence of topologies; metrizable; scattered; Čech–Stone compactification},
language = {eng},
number = {3},
pages = {295-306},
publisher = {Charles University in Prague, Faculty of Mathematics and Physics},
title = {Order intervals in $C(K)$. Compactness, coincidence of topologies, metrizability},
url = {http://eudml.org/doc/299039},
volume = {62 63},
year = {2022},
}

TY - JOUR
AU - Lipecki, Zbigniew
TI - Order intervals in $C(K)$. Compactness, coincidence of topologies, metrizability
JO - Commentationes Mathematicae Universitatis Carolinae
PY - 2022
PB - Charles University in Prague, Faculty of Mathematics and Physics
VL - 62 63
IS - 3
SP - 295
EP - 306
AB - Let $K$ be a compact space and let $C(K)$ be the Banach lattice of real-valued continuous functions on $K$. We establish eleven conditions equivalent to the strong compactness of the order interval $[0,x]$ in $C(K)$, including the following ones: (i) $\lbrace x>0\rbrace $ consists of isolated points of $K$; (ii) $[0,x]$ is pointwise compact; (iii) $[0,x]$ is weakly compact; (iv) the strong topology and that of pointwise convergence coincide on $[0,x]$; (v) the strong and weak topologies coincide on $[0,x]$. Moreover, the weak topology and that of pointwise convergence coincide on $[0,x]$ if and only if $\lbrace x>0\rbrace $ is scattered. Finally, the weak topology on $[0,x]$ is metrizable if and only if the topology of pointwise convergence on $[0,x]$ is such if and only if $\lbrace x>0\rbrace $ is countable.
LA - eng
KW - real linear lattice; order interval; locally solid; Banach lattice $C(K)$; strongly compact; weakly compact; pointwise compact; coincidence of topologies; metrizable; scattered; Čech–Stone compactification
UR - http://eudml.org/doc/299039
ER -

References

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  1. Aliprantis C. D., Burkinshaw O., Positive Operators, Pure and Applied Mathematics, 119, Academic Press, Orlando, 1985. Zbl1098.47001MR0809372
  2. Aliprantis C. D., Burkinshaw O., 10.1090/surv/105, Mathematical Surveys and Monographs, 105, American Mathematical Society, Providence, 2003. MR2011364DOI10.1090/surv/105
  3. Arkhangel'skiĭ A. V., 10.1007/978-94-011-2598-7_4, Mathematics and Its Applications (Soviet Series), 78, Kluwer Academic Publishers Group, Dordrecht, 1992. MR1144519DOI10.1007/978-94-011-2598-7_4
  4. Engelking R., General Topology, Monografie Matematyczne, 60, PWN—Polish Scientific Publishers, Warszawa, 1977. Zbl0684.54001MR0500780
  5. Floret K., Weakly Compact Sets, Lectures held at S.U.N.Y., Buffalo, 1978, Lecture Notes in Mathematics, 801, Springer, Berlin, 1980. MR0576235
  6. Lipecki Z., 10.4064/cm7726-5-2019, Colloq. Math. 160 (2020), no. 1, 119–132. MR4071818DOI10.4064/cm7726-5-2019
  7. Lipecki Z., 10.4064/cm8624-11-2021, Colloq. Math. 168 (2022), no. 2, 297–309. MR4416011DOI10.4064/cm8624-11-2021
  8. van Mill J., The Infinite-Dimensional Topology of Function Spaces, North-Holland Mathematical Library, 64, North-Holland Publishing Co., Amsterdam, 2001. Zbl0969.54003MR1851014
  9. Semadeni Z., Banach Spaces of Continuous Functions. Vol. I, Monografie Matematyczne, 55, PWN—Polish Scientific Publishers, Warszawa, 1971. MR0296671

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