Quantitative form of the Luzin $C$-property

We prove the following statement, which is a quantitative form of the Luzin theorem on $C$-property: Let $(X, d, μ)$ be a bounded metric space with metric $d$ and regular Borel measure $μ$ that are related to one another by the doubling condition. Then, for any function $f$ measurable on $X$, there...

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Datum:2010
Hauptverfasser: Krotov, V. G., Кротов, В. Г.
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Sprache:Russisch
Englisch
Veröffentlicht: Institute of Mathematics, NAS of Ukraine 2010
Online Zugang:https://umj.imath.kiev.ua/index.php/umj/article/view/2874
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Назва журналу:Ukrains’kyi Matematychnyi Zhurnal
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Ukrains’kyi Matematychnyi Zhurnal
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author Krotov, V. G.
Кротов, В. Г.
Кротов, В. Г.
author_facet Krotov, V. G.
Кротов, В. Г.
Кротов, В. Г.
author_sort Krotov, V. G.
baseUrl_str https://umj.imath.kiev.ua/index.php/umj/oai
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datestamp_date 2020-03-18T19:39:19Z
description We prove the following statement, which is a quantitative form of the Luzin theorem on $C$-property: Let $(X, d, μ)$ be a bounded metric space with metric $d$ and regular Borel measure $μ$ that are related to one another by the doubling condition. Then, for any function $f$ measurable on $X$, there exist a positive increasing function $η ∈ Ω\; \left(η(+0) = 0\right.$ and $η(t)t^{−a}$ decreases for a certain $\left. a > 0\right)$, a nonnegative function $g$ measurable on $X$, and $a$ set $E ⊂ X, μE = 0$, for which $$|f(x)−f(y)| ⩽ [g(x)+g(y)]η(d(x,y)),\;x,y ∈ X \setminus E.$$ If $f ∈ L^p(X),\; p >0$, then it is possible to choose $g$ belonging to $L^p (X)$.
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spelling umjimathkievua-article-28742020-03-18T19:39:19Z Quantitative form of the Luzin $C$-property Количественная форма $C$-свойства Лузина Krotov, V. G. Кротов, В. Г. Кротов, В. Г. We prove the following statement, which is a quantitative form of the Luzin theorem on $C$-property: Let $(X, d, μ)$ be a bounded metric space with metric $d$ and regular Borel measure $μ$ that are related to one another by the doubling condition. Then, for any function $f$ measurable on $X$, there exist a positive increasing function $η ∈ Ω\; \left(η(+0) = 0\right.$ and $η(t)t^{−a}$ decreases for a certain $\left. a > 0\right)$, a nonnegative function $g$ measurable on $X$, and $a$ set $E ⊂ X, μE = 0$, for which $$|f(x)−f(y)| ⩽ [g(x)+g(y)]η(d(x,y)),\;x,y ∈ X \setminus E.$$ If $f ∈ L^p(X),\; p >0$, then it is possible to choose $g$ belonging to $L^p (X)$. Доведено наступне твердження, яке є кількісною формою теореми Лузіна про $C$-властивість. Нехай $(X, d, μ)$—обмежений метричний простір із метрикою $d$ і регулярною борелевого мірою $μ$, що пов'язані умовою подвоєння. Тоді для будь-якої вимірної на $X$ функції $f$ існують додатна зростаюча функція $η ∈ Ω \;\left(η(+0) = 0\right.$ і $η(t)t^{−a}$ спадає при деякому $\left. a > 0\right)$, вимірна на $X$ невід'ємна функція $g$ та множина $E ⊂ X, μE = 0$, для яких $$|f(x)−f(y)| ⩽ [g(x)+g(y)]η(d(x,y)),\;x,y ∈ X\setminus E.$$ Якщо $f ∈ L^p(X),\; p >0$, то можна вибрати $g \in L^p (X)$. Institute of Mathematics, NAS of Ukraine 2010-03-25 Article Article application/pdf https://umj.imath.kiev.ua/index.php/umj/article/view/2874 Ukrains’kyi Matematychnyi Zhurnal; Vol. 62 No. 3 (2010); 387–395 Український математичний журнал; Том 62 № 3 (2010); 387–395 1027-3190 rus en https://umj.imath.kiev.ua/index.php/umj/article/view/2874/2499 https://umj.imath.kiev.ua/index.php/umj/article/view/2874/2500 Copyright (c) 2010 Krotov V. G.
spellingShingle Krotov, V. G.
Кротов, В. Г.
Кротов, В. Г.
Quantitative form of the Luzin $C$-property
title Quantitative form of the Luzin $C$-property
title_alt Количественная форма $C$-свойства Лузина
title_full Quantitative form of the Luzin $C$-property
title_fullStr Quantitative form of the Luzin $C$-property
title_full_unstemmed Quantitative form of the Luzin $C$-property
title_short Quantitative form of the Luzin $C$-property
title_sort quantitative form of the luzin $c$-property
url https://umj.imath.kiev.ua/index.php/umj/article/view/2874
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