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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">RUDN Journal of Engineering Research</journal-id><journal-title-group><journal-title xml:lang="en">RUDN Journal of Engineering Research</journal-title><trans-title-group xml:lang="ru"><trans-title>Вестник Российского университета дружбы народов. Серия: Инженерные исследования</trans-title></trans-title-group></journal-title-group><issn publication-format="print">2312-8143</issn><issn publication-format="electronic">2312-8151</issn><publisher><publisher-name xml:lang="en">Peoples’ Friendship University of Russia named after Patrice Lumumba (RUDN University)</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">42384</article-id><article-id pub-id-type="doi">10.22363/2312-8143-2024-25-3-288-295</article-id><article-id pub-id-type="edn">YNNOZA</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">Exact Partial Solution in a Form of Convex Tetragons Interacting According to the Arbitrary Law for Four Bodies</article-title><trans-title-group xml:lang="ru"><trans-title>Точные и частные решения в форме выпуклых четырехугольников, взаимодействующих по закону четырех тел</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-8115-8253</contrib-id><contrib-id contrib-id-type="spin">5157-4093</contrib-id><name-alternatives><name xml:lang="en"><surname>Perepelkina</surname><given-names>Yulianna V.</given-names></name><name xml:lang="ru"><surname>Перепелкина</surname><given-names>Юлианна Вячеславовна</given-names></name></name-alternatives><bio xml:lang="en"><p>Candidate of Physical and Mathematical Sciences, Head of Scientific Information Department of Mechanics</p></bio><bio xml:lang="ru"><p>кандидат физико-математических наук, заведующая ОНИ по механике</p></bio><email>amadeycity@yandex.com</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Russian Institute for Scientific and Technical Information of Russian Academy of Sciences</institution></aff><aff><institution xml:lang="ru">Всероссийский институт научной и технической информации РАН</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2024-12-15" publication-format="electronic"><day>15</day><month>12</month><year>2024</year></pub-date><volume>25</volume><issue>3</issue><issue-title xml:lang="en">VOL 25, NO3 (2024)</issue-title><issue-title xml:lang="ru">ТОМ 25, №3 (2024)</issue-title><fpage>288</fpage><lpage>295</lpage><history><date date-type="received" iso-8601-date="2025-01-10"><day>10</day><month>01</month><year>2025</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2024, Perepelkina Y.V.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2024, Перепелкина Ю.В.</copyright-statement><copyright-year>2024</copyright-year><copyright-holder xml:lang="en">Perepelkina Y.V.</copyright-holder><copyright-holder xml:lang="ru">Перепелкина Ю.В.</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-nc/4.0/legalcode</ali:license_ref></license></permissions><self-uri xlink:href="https://journals.rudn.ru/engineering-researches/article/view/42384">https://journals.rudn.ru/engineering-researches/article/view/42384</self-uri><abstract xml:lang="en"><p>We prove the existence of exact partial solutions in the form of convex quadrilaterals in the general problem of four bodies mutually acting according to an arbitrary law ~1/r<sup>к</sup> , where k ≥ 2. For each fixed k ≥ 2 the distances between the bodies and their corresponding sets of four masses are found, which determine private solutions in the form of square, rhombus, deltoid and trapezoid. On the basis of the methodology of classical works the equations of motion in Raus - Lyapunov variables in the general problem of four bodies interacting according to a completely arbitrary law are derived, as it took place when Laplace proved the existence of exact partial triangular solutions of the general problem of three bodies with arbitrary masses. An explanation of the problem of existence of this type of solutions is given, due, in particular, to the more complicated geometry of quadrangular solutions in comparison with triangular ones, the existence of which is proved in the general three-body problem by the classics of celestial mechanics. It is suggested that if the arbitrariness of the interaction law is somewhat restricted, it is possible to prove by numerical methods the existence of exact partial solutions at different fixed values k ≥ 2 and unequal values of the masses of the four bodies.</p></abstract><trans-abstract xml:lang="ru"><p>Доказано существование точных частных решений в форме выпуклых четырехугольников в общей задаче четырех тел, взаимодействующих по произвольному закону ~1/r<sup>к</sup> , где k ≥ 2. Для каждого фиксированного k ≥ 2 найдены расстояния между телами и соответствующие им совокупности четырех масс, определяющих частные решении в форме квадрата, ромба, дельтоида и трапеции. На основе методологии работ классиков выведены уравнения движения в переменных Рауса - Ляпунова в общей задаче четырех тел, взаимодействующих по совершенно произвольному закону, как это имело место при доказательстве Лапласом существования точных частных треугольных решений общей задачи трех тел с произвольными массами. Приведено объяснение проблемы существования данного типа решений, обусловленной, в частности, более сложной геометрией четырехугольных решений по сравнению с треугольными, существование которых доказано в общей задаче трех тел классиками небесной механики. Высказывается предположение, что если произвольность закона взаимодействия несколько ограничить, можно численными методами доказать существование точных частных решений при различных фиксированных значениях k ≥ 2 и неравных значениях масс четырех тел.</p></trans-abstract><kwd-group xml:lang="en"><kwd>celestial mechanics</kwd><kwd>four-body problem</kwd><kwd>Raus - Lyapunov variables</kwd><kwd>particular solutions</kwd><kwd>laws of interaction</kwd><kwd>bounded problems</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>небесная механика</kwd><kwd>задача четырех тел</kwd><kwd>переменные Рауса - Ляпунова</kwd><kwd>частные решения</kwd><kwd>законы взаимодействия</kwd><kwd>ограниченные задачи</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Liouville J. Sur un cas particulier du problème de trois corps (Extrait). Comptes Rendus Acad. Sci. 1842; 14(14):503-506. 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