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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">Discrete and Continuous Models and Applied Computational Science</journal-id><journal-title-group><journal-title xml:lang="en">Discrete and Continuous Models and Applied Computational Science</journal-title><trans-title-group xml:lang="ru"><trans-title>Discrete and Continuous Models and Applied Computational Science</trans-title></trans-title-group></journal-title-group><issn publication-format="print">2658-4670</issn><issn publication-format="electronic">2658-7149</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">8229</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">Looking for Families of Periodic Solutions of Ordinary Differential Equations Systems by Normal Form Method. Part I</article-title><trans-title-group xml:lang="ru"><trans-title>Поиск семейств периодических решений обыкновенных дифференциальных уравнений с помощью метода нормальной формы. Часть 1</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Edneral</surname><given-names>V F</given-names></name><name xml:lang="ru"><surname>Еднерал</surname><given-names>Виктор Фёдорович</given-names></name></name-alternatives><bio xml:lang="en">Department of Applied Informatics and Probability Theory Peoples’ Friendship University of Russia 6, Miklukho-Maklaya str., Moscow, Russian Federation, 117198</bio><bio xml:lang="ru">Кафедра прикладной информатики и теории вероятностей Российский университет дружбы народов ул. Миклухо-Маклая, д.6, Москва, Россия, 117198</bio><email>victor.edneral@yandex.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Timofeevskaya</surname><given-names>O D</given-names></name><name xml:lang="ru"><surname>Тимофеевская</surname><given-names>Ольга Дмитриевна</given-names></name></name-alternatives><bio xml:lang="en">Physical Department</bio><bio xml:lang="ru">Кафедра физики высоких энергий и квантовой теории поля Физический факультет</bio><email>olgamsu1@yandex.ru</email><xref ref-type="aff" rid="aff2"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State University (SINP MSU)</institution></aff><aff><institution xml:lang="ru">НИИ ядерной физики имени Д.В. Скобельцина Московский государственный университет им. М.В. Ломоносова (НИИЯФ МГУ)</institution></aff></aff-alternatives><aff-alternatives id="aff2"><aff><institution xml:lang="en">Lomonosov Moscow State University</institution></aff><aff><institution xml:lang="ru">Московский государственный университет им. М.В. Ломоносова</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2014-03-15" publication-format="electronic"><day>15</day><month>03</month><year>2014</year></pub-date><issue>3</issue><issue-title xml:lang="en">NO3 (2014)</issue-title><issue-title xml:lang="ru">№3 (2014)</issue-title><fpage>28</fpage><lpage>45</lpage><history><date date-type="received" iso-8601-date="2016-09-08"><day>08</day><month>09</month><year>2016</year></date></history><permissions><copyright-statement xml:lang="ru">Copyright ©; 2014, Еднерал В.Ф., Тимофеевская О.Д.</copyright-statement><copyright-year>2014</copyright-year><copyright-holder xml:lang="ru">Еднерал В.Ф., Тимофеевская О.Д.</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/">http://creativecommons.org/licenses/by/4.0</ali:license_ref></license></permissions><self-uri xlink:href="https://journals.rudn.ru/miph/article/view/8229">https://journals.rudn.ru/miph/article/view/8229</self-uri><abstract xml:lang="en">In this paper, we discuss the application of resonant normal form method to the search of periodic solutions families of autonomous systems of explicit ordinary differential equations with polynomial nonlinearities in the right parts. Further, using formulated by Prof. A. D. Bruno sufficient convergence condition for the normalizing transformation, we find local families of periodic solutions of systems of such ODE in the vicinity of stationary points. In this unified approach both Hamiltonian and not Hamiltonian systems are investigated. For reasons of volume the article is divided into two parts. In the first part we describe an algorithm of implementing the method of normal forms. Software packages created by the authors are briefly described separately. We have developed a RLISP language package for working in REDUCE system, and for MATHEMATICA system a package on the external language of this system. This packages allow us, in particular, to obtain formulas describing local (containing a fixed point) families of periodic solutions. The results of calculations are presented in the form of Fourier series segments of a given length with frequency and coefficients themselves calculated as parameter series segments. This representation corresponds to the special case of segments of Poisson series. It is important that using a single algorithm, one can study both two-dimensional and higher-order systems. The second part is devoted to fourth-order systems. The comparison of tabulation of formulas obtained with numerical solutions of the corresponding equations shows good quantitative agreement. The approach described can be used for modeling of physical and biological systems.</abstract><trans-abstract xml:lang="ru">В настоящей работе кратко обсуждается применение метода резонансной нормальной формы к поиску семейств периодических решений автономных систем обыкновенных дифференциальных уравнений, разрешённых относительно производных и с полиномиальными нелинейностями в правых частях. При использовании сформулированного проф. А.Д. Брюно достаточном условии сходимости нормализующего преобразования, находятся локальные семейства периодических решений систем таких ОДУ в окрестностях стационарных точек. При этом в едином подходе исследуются как гамильтоновы, так и не гамильтоновы системы. По соображениям объёма статья разбита на две части. В первой части описан алгоритм реализации метода нормальных форм. Отдельно кратко описаны созданные авторами программные пакеты. На языке RLISP разработан пакет для работы в системе REDUCE, а для работы с системой MATHEMATICA написан пакет на внешнем языке этой системы. Пакеты позволяют, в частности, получать формулы, описывающие локальные (содержащие неподвижную точку) семейства периодических решений. Результаты вычислений представляются в виде отрезков рядов Фурье заданной длины с частотой и коэффициентами, вычисленными в виде отрезков степенных рядов по параметру. Такое представление соответствует частному случаю отрезков рядов Пуассона. Важно, что при помощи единого алгоритма возможно изучать как двумерные, так и системы высоких порядков. Вторая часть статьи посвящена системам четвёртого порядка. Сравнение табуляции полученных формул с численными решениями соответствующих уравнений показывает хорошее количественное согласие. Описываемый подход может быть использован при моделировании физических и биологических систем.</trans-abstract><kwd-group xml:lang="en"><kwd>resonant normal form</kwd><kwd>dynamical systems</kwd><kwd>local periodic families of solutions</kwd><kwd>computer algebra</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>резонансная нормальная форма</kwd><kwd>динамические системы</kwd><kwd>локальные периодические семейства решений</kwd><kwd>компьютерная алгебра</kwd></kwd-group></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Arnold V.I., Anosov D.V. 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