Naturalness of the Class of Lebesgue--Borel--Hausdorff Measurable Functions
Matematičeskie zametki, Tome 95 (2014) no. 4, pp. 554-563.

Voir la notice de l'article provenant de la source Math-Net.Ru

It is well known that the family of all continuous functions on a topological space contains all constant functions and is closed with respect to the usual pointwise operations (addition, multiplication, finite supremum and infimum, division) and uniform convergence. The complete description of such function families (normal families) was given by Borel, Lebesgue, and Hausdorff. The normal families turned out to be exactly the families of all functions measurable with respect to multiplicative $\sigma$-additive families of sets. In 1914, Hausdorff also described the normal envelope of an arbitrary family of functions. If uniform convergence is replaced by pointwise convergence, then the notions of completely normal family and completely normal envelope arise. In 1977, Regoli described all completely normal families. They turned out to be precisely the families of all functions measurable with respect to $\sigma$-algebras of sets. Moreover, Regoli described the completely normal envelope of a specific family of functions. The present paper gives descriptive and some constructive characterizations of the completely normal envelope of an arbitrary family of functions.
Keywords: normal family of functions, completely normal family, normal envelope, completely normal envelope, pointwise convergence, measurable function.
@article{MZM_2014_95_4_a6,
     author = {V. K. Zakharov and T. V. Rodionov},
     title = {Naturalness of the {Class} of {Lebesgue--Borel--Hausdorff} {Measurable} {Functions}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {554--563},
     publisher = {mathdoc},
     volume = {95},
     number = {4},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2014_95_4_a6/}
}
TY  - JOUR
AU  - V. K. Zakharov
AU  - T. V. Rodionov
TI  - Naturalness of the Class of Lebesgue--Borel--Hausdorff Measurable Functions
JO  - Matematičeskie zametki
PY  - 2014
SP  - 554
EP  - 563
VL  - 95
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_2014_95_4_a6/
LA  - ru
ID  - MZM_2014_95_4_a6
ER  - 
%0 Journal Article
%A V. K. Zakharov
%A T. V. Rodionov
%T Naturalness of the Class of Lebesgue--Borel--Hausdorff Measurable Functions
%J Matematičeskie zametki
%D 2014
%P 554-563
%V 95
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_2014_95_4_a6/
%G ru
%F MZM_2014_95_4_a6
V. K. Zakharov; T. V. Rodionov. Naturalness of the Class of Lebesgue--Borel--Hausdorff Measurable Functions. Matematičeskie zametki, Tome 95 (2014) no. 4, pp. 554-563. http://geodesic.mathdoc.fr/item/MZM_2014_95_4_a6/

[1] F. Hausdorff, Grundzüge der Mengenlehre, Veit Comp., Leipzig, 1914 | MR | Zbl

[2] F. Khausdorf, Teoriya mnozhestv, URSS, M., 2004

[3] V. K. Zakharov, “Teoremy Khausdorfa ob izmerimykh funktsiyakh i novyi klass ravnomernykh funktsii”, Vestn. Mosk. un-ta. Ser. 1. Matem. mekh., 2008, no. 1, 3–8 | MR | Zbl

[4] V. K. Zakharov, T. V. Rodionov, “Klass ravnomernykh funktsii i ego sootnoshenie s klassom izmerimykh funktsii”, Matem. zametki, 84:6 (2008), 809–824 | DOI | MR | Zbl

[5] G. Regoli, “Some characterization of sets of measurable functions”, Amer. Math. Monthly, 84:6 (1977), 455–458 | DOI | MR | Zbl

[6] Z. Semadeni, Banach Spaces of Continuous Functions, Vol. 1, Monografie Matematyczne, 55, PWN, Warszawa, 1971 | MR | Zbl

[7] N. Dinculianu, Vector Measures, Oxford Univ. Press, London, 1967

[8] V. K. Zakharov, T. V. Rodionov, “Klassifikatsiya borelevskikh mnozhestv i funktsii na proizvolnom prostranstve”, Matem. sb., 199:6 (2008), 49–84 | DOI | MR | Zbl

[9] V. K. Zakharov, “Klassifikatsiya borelevskikh mnozhestv i funktsii dlya proizvolnogo prostranstva”, Dokl. RAN, 385:5 (2002), 596–598 | MR | Zbl

[10] V. K. Zakharov, “Novye klassy funktsii, svyazannye s obschimi semeistvami mnozhestv”, Dokl. RAN, 407:2 (2006), 167–171 | MR

[11] V. K. Zakharov, T. V. Rodionov, “A fine correlation between Baire and Borel functional hierarchies”, Acta Math. Hungar., 142:2 (2014), 384–402 | MR