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<article 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" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="research-article" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Russian Universities Reports. Mathematics</journal-id><journal-title-group><journal-title xml:lang="en">Russian Universities Reports. Mathematics</journal-title><trans-title-group xml:lang="ru"><trans-title>Вестник российских университетов. Математика</trans-title></trans-title-group></journal-title-group><issn publication-format="print">2686-9667</issn><issn publication-format="electronic">2782-3342</issn><publisher><publisher-name xml:lang="en">Tambov State University - G.R. Derzhavin</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">297299</article-id><article-id pub-id-type="doi">10.20310/1810-0198-2019-24-125-33-38</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>Articles</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>Статьи</subject></subj-group><subj-group subj-group-type="article-type"><subject>Research Article</subject></subj-group></article-categories><title-group><article-title xml:lang="en">On exact triangle inequalities in (q1; q2) -quasimetric spaces</article-title><trans-title-group xml:lang="ru"><trans-title>О точных неравенствах треугольника в (q1; q2)-квазиметрических пространствах</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Zhukovskaya</surname><given-names>Zukhra T.</given-names></name><name xml:lang="ru"><surname>Жуковская</surname><given-names>Зухра Тагировна</given-names></name></name-alternatives><bio xml:lang="en"><p>Candidate of Physics and Mathematics, Researcher at the Center for Nonlinear Analysis and Optimization</p></bio><bio xml:lang="ru"><p>кандидат физико-математических наук, научный сотрудник центра нелинейного анализа и оптимизации</p></bio><email>zyxra2@yandex.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Zhukovskiy</surname><given-names>Sergey E.</given-names></name><name xml:lang="ru"><surname>Жуковский</surname><given-names>Сергей Евгеньевич</given-names></name></name-alternatives><bio xml:lang="en"><p>Candidate of Physics and Mathematics, Senior Researcher at the Center for Nonlinear Analysis and Optimization, Senior Researcher.</p></bio><bio xml:lang="ru"><p>кандидат физико-математических наук, старший научный сотрудник центра нелинейного анализа и оптимизации, старший научный сотрудник</p></bio><email>s-ezhuk@yandex.ru</email><xref ref-type="aff" rid="aff1"/><xref ref-type="aff" rid="aff2"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Richik</surname><given-names>Sengupta</given-names></name><name xml:lang="ru"><surname>Сенгупта</surname><given-names>Ричик</given-names></name></name-alternatives><bio xml:lang="en"><p>Post-Graduate Student, Faculty of Physics, Mathematics and Natural Sciences</p></bio><bio xml:lang="ru"><p>аспирант, факультет физико-математических и естественных наук</p></bio><email>veryricheek@hotmail.com</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">RUDN University</institution></aff><aff><institution xml:lang="ru">ФГАОУ ВО «Российский университет дружбы народов»</institution></aff></aff-alternatives><aff-alternatives id="aff2"><aff><institution xml:lang="en">V. A. Trapeznikov Institute of Control Sciences of RAS</institution></aff><aff><institution xml:lang="ru">ФГБУН «Институт проблем управления им. В. А. Трапезникова» Российской академии наук</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2019-12-15" publication-format="electronic"><day>15</day><month>12</month><year>2019</year></pub-date><volume>24</volume><issue>125</issue><issue-title xml:lang="en">VOL 24, NO125 (2019)</issue-title><issue-title xml:lang="ru">ТОМ 24, №125 (2019)</issue-title><fpage>33</fpage><lpage>38</lpage><history><date date-type="received" iso-8601-date="2025-06-20"><day>20</day><month>06</month><year>2025</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2025, Zhukovskaya Z.T., Zhukovskiy S.E., Richik S.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2025, Жуковская З.Т., Жуковский С.Е., Сенгупта Р.</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="en">Zhukovskaya Z.T., Zhukovskiy S.E., Richik S.</copyright-holder><copyright-holder xml:lang="ru">Жуковская З.Т., Жуковский С.Е., Сенгупта Р.</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/><license><ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://creativecommons.org/licenses/by/4.0</ali:license_ref></license></permissions><self-uri xlink:href="https://journals.rcsi.science/2686-9667/article/view/297299">https://journals.rcsi.science/2686-9667/article/view/297299</self-uri><abstract xml:lang="en"><p>For arbitrary ( q 1 ; q 2) -quasimetric space, it is proved that there exists a function f; such that f -triangle inequality is more exact than any ( q 1 ; q 2) -triangle inequality. It is shown that this function f is the least one in the set of all concave continuous functions g for which g -triangle inequality hold.</p></abstract><trans-abstract xml:lang="ru"><p>Для произвольного ( q 1 ; q 2) -квазиметрического пространства доказано существование функции f; для которой f -неравенство треугольника точнее, чем ( q 1 ; q 2) -неравенство треугольника. Показано, что найденная функция f является наименьшей функцией в классе вогнутых непрерывных функций g; для которых выполняется g -неравенство треугольника.</p></trans-abstract><kwd-group xml:lang="en"><kwd>(q</kwd><kwd>q) -quasimetric space</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>(q</kwd><kwd>q) -квазиметрическое пространство</kwd></kwd-group></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>А. В. Арутюнов, А. В. Грешнов, “Теория (q1; q2) -квазиметрических пространств и точки совпадения”, ДАН, 469:5 (2016), 527-531.</mixed-citation></ref><ref id="B2"><label>2.</label><mixed-citation>А. В. Арутюнов, Лекции по выпуклому и многозначному анализу, Физматлит, М., 2014.</mixed-citation></ref></ref-list></back></article>
