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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">cheb</journal-id><journal-title-group><journal-title xml:lang="ru">Чебышевский сборник</journal-title><trans-title-group xml:lang="en"><trans-title>Chebyshevskii Sbornik</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2226-8383</issn><publisher><publisher-name>Tula State Lev Tolstoy  Pedagogical University</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.22405/2226-8383-2023-24-1-237-242</article-id><article-id custom-type="elpub" pub-id-type="custom">cheb-1487</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>Краткие сообщения</subject></subj-group></article-categories><title-group><article-title>О множестве исключений в произведении множеств натуральных чисел с асимптотической плотностью 1</article-title><trans-title-group xml:lang="en"><trans-title>On the set of exceptions in the product of sets of natural numbers with asymptotic density 1</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Штейников</surname><given-names>Юрий Николаевич</given-names></name><name name-style="western" xml:lang="en"><surname>Shteinikov</surname><given-names>Yuri Nikolaevich</given-names></name></name-alternatives><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Федеральный научный центр «Научно-исследовательский институт системных исследований Российской академии наук»</institution><country>Россия</country></aff><aff xml:lang="en"><institution>Federal Research Center “Research Institute of System Research&#13;
of the Russian Academy of Sciences”</institution><country>Russian Federation</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2023</year></pub-date><pub-date pub-type="epub"><day>25</day><month>05</month><year>2023</year></pub-date><volume>24</volume><issue>1</issue><fpage>237</fpage><lpage>242</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Штейников Ю.Н., 2023</copyright-statement><copyright-year>2023</copyright-year><copyright-holder xml:lang="ru">Штейников Ю.Н.</copyright-holder><copyright-holder xml:lang="en">Shteinikov Y.N.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://www.chebsbornik.ru/jour/article/view/1487">https://www.chebsbornik.ru/jour/article/view/1487</self-uri><abstract><p>В статье изучается следующая задача. Пусть имеется два подмножества множества натуральных чисел, которые мы обозначим как 𝐴 и 𝐵. Пусть дополнительно известно также, что асимптотическая плотность этих множеств 𝐴,𝐵 равна 1. Мы определяем множество натуральных чисел, которые являются представимыми в виде произведения этих множеств 𝐴𝐵, то есть такие элементы 𝑎𝑏, где 𝑎 ∈ 𝐴, 𝑏 ∈ 𝐵. Мы изучаем свойства это-го подмножества произведений во множестве всех натуральных чисел. Авторы S. Bettin, D. Koukoulopoulos и C. Sanna в статье [<xref ref-type="bibr" rid="cit1">1</xref>] доказали помимо всего прочего, что плотность множества 𝐴𝐵 также равна 1. Более того была выведена количественная версия этого утверждения, а именно получена оценка на множество N ∖ 𝐴𝐵, которое мы обозначим через 𝐴𝐵. А именно, этими авторами в случае когда известны количественные верхние оценки на 𝐴 ∩ [1, 𝑥] = 𝛼(𝑥)𝑥,𝐵 ∩ [1, 𝑥] = 𝛽(𝑥)𝑥, 𝛼(𝑥), 𝛽(𝑥) = 𝑂(1/(log 𝑥)𝑎), 𝑥 → ∞ вы-ведена и верхняя оценка на множество 𝐴𝐵 ∩ [1, 𝑥]. В данной работе мы изучаем случай когда 𝛼, 𝛽 стремятся к нулю медленнее чем в вышеуказанном случае и несколько уточняем верхнюю оценку на множество 𝐴𝐵 ∩ [1, 𝑥]. В настоящей статье мы рассматриваем случай 𝛼(𝑥), 𝛽(𝑥) = 𝑂(︀ 1/((log log 𝑥)^𝑎))︀при некотором фиксированном 𝑎 &gt; 1. Мы заимствуемподходы, аргументы и схему доказательства из упомянутой работы трех авторов S. Bettin, D. Koukoulopoulos и C. Sanna[<xref ref-type="bibr" rid="cit1">1</xref>].</p></abstract><trans-abstract xml:lang="en"><p>The article examines the following problem. Let there be two subsets of the set of natural numbers, which we denote as 𝐴 and 𝐵. Let it also be additionally known that the asymptotic density of these sets 𝐴,𝐵 is 1. We define the set of natural numbers that are representableas the product of these sets 𝐴𝐵, that is, such elements 𝑎𝑏, where 𝑎 ∈ 𝐴, 𝑏 ∈ 𝐵. We study the properties of this subset of products in the set of all natural numbers. The authors S.Bettin, D. Koukoulopoulos and C. Sanna in the article [<xref ref-type="bibr" rid="cit1">1</xref>] proved, among other things, that the density of the set 𝐴𝐵 is also equal to 1. Moreover, a quantitative version of this statement was derived, namely, an estimate was obtained for the set N ∖ 𝐴𝐵, which we will denote by 𝐴𝐵. Namely, by these authors, in the case when quantitative upper bounds are known for 𝐴 ∩ [1, 𝑥] = 𝛼(𝑥)𝑥,𝐵 ∩ [1, 𝑥] = 𝛽(𝑥)𝑥, 𝛼(𝑥), 𝛽(𝑥) = 𝑂(1/(log 𝑥)𝑎), 𝑥 → ∞ the upper bound on the set 𝐴𝐵 ∩ [1, 𝑥] is also derived. In this paper, we study the case when 𝛼, 𝛽 tend to zeroslower than in the above case and somewhat refine the upper bound on the set 𝐴𝐵 ∩ [1, 𝑥]. In this paper we consider the case of 𝛼(𝑥), 𝛽(𝑥) = 𝑂(︀ 1/(log log 𝑥)𝑎)︀ for some fixed 𝑎 &gt; 1. We borrow approaches, arguments and proof scheme from the mentioned work of three authors S. Bettin, D. Koukoulopoulos and C. Sanna[<xref ref-type="bibr" rid="cit1">1</xref>].</p></trans-abstract><kwd-group xml:lang="ru"><kwd>натуральные числа</kwd><kwd>плотность</kwd><kwd>гладкие числа</kwd><kwd>произведение.</kwd></kwd-group><kwd-group xml:lang="en"><kwd>integer numbers</kwd><kwd>density</kwd><kwd>smooth numbers</kwd><kwd>product.</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Bettin, S., Koukoulopoulos, D., Sanna, C. A note on the natural density of product sets //</mixed-citation><mixed-citation xml:lang="en">Bettin S., Koukoulopoulos D., Sanna C. “A note on the natural density of product sets” Bull.</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Bull. Lond. Math. Soc. 2021. Vol. 53, №. 5, P. 1407-1413.</mixed-citation><mixed-citation xml:lang="en">Lond. Math. 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