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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">35920</article-id><article-id pub-id-type="doi">10.22363/2658-4670-2023-31-3-242-246</article-id><article-id pub-id-type="edn">XYOZDS</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">Hodge-de Rham Laplacian and geometric criteria for gravitational waves</article-title><trans-title-group xml:lang="ru"><trans-title>Лапласиан Ходжа-де Рама и геометрический критерий для гравитационных волн</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-2527-5268</contrib-id><name-alternatives><name xml:lang="en"><surname>Babourova</surname><given-names>Olga V.</given-names></name><name xml:lang="ru"><surname>Бабурова</surname><given-names>О. В.</given-names></name></name-alternatives><bio xml:lang="en"><p>Professor, Doctor of Sciences in Physics and Mathematics, Professor at Department Physics</p></bio><email>ovbaburova@madi.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-8899-1894</contrib-id><name-alternatives><name xml:lang="en"><surname>Frolov</surname><given-names>Boris N.</given-names></name><name xml:lang="ru"><surname>Фролов</surname><given-names>Б. Н.</given-names></name></name-alternatives><bio xml:lang="en"><p>Professor, Doctor of Sciences in Physics and Mathematics, Professor at Department of Theoretical Physics, Institute of Physics, Technology and Information Systems</p></bio><email>bn.frolov@mpgu.su</email><xref ref-type="aff" rid="aff2"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Moscow Automobile and Road Construction State Technical University</institution></aff><aff><institution xml:lang="ru">Московский автодорожный государственный технический университет</institution></aff></aff-alternatives><aff-alternatives id="aff2"><aff><institution xml:lang="en">Moscow Pedagogical State University</institution></aff><aff><institution xml:lang="ru">Московский педагогический государственный университет</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2023-09-12" publication-format="electronic"><day>12</day><month>09</month><year>2023</year></pub-date><volume>31</volume><issue>3</issue><issue-title xml:lang="en">VOL 31, NO3 (2023)</issue-title><issue-title xml:lang="ru">ТОМ 31, №3 (2023)</issue-title><fpage>242</fpage><lpage>246</lpage><history><date date-type="received" iso-8601-date="2023-09-12"><day>12</day><month>09</month><year>2023</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2023, Babourova O.V., Frolov B.N.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2023, Бабурова О.В., Фролов Б.Н.</copyright-statement><copyright-year>2023</copyright-year><copyright-holder xml:lang="en">Babourova O.V., Frolov B.N.</copyright-holder><copyright-holder xml:lang="ru">Бабурова О.В., Фролов Б.Н.</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</ali:license_ref></license></permissions><self-uri xlink:href="https://journals.rudn.ru/miph/article/view/35920">https://journals.rudn.ru/miph/article/view/35920</self-uri><abstract xml:lang="en"><p style="text-align: justify;">The curvature tensor <span class="math inline">\(\hat{R}\)</span> of a manifold is called harmonic, if it obeys the condition <span class="math inline">\(\Delta^{\text{(HR)}}\hat{R}=0\)</span>, where <span class="math inline">\(\Delta^{\text{(HR)}}=DD^{\ast} +&#13;
D^{\ast}D\)</span> is the Hodge–de Rham Laplacian. It is proved that all solutions of the Einstein equations in vacuum, as well as all solutions of the Einstein–Cartan theory in vacuum have a harmonic curvature. The statement that only solutions of Einstein’s equations of type <span class="math inline">\(N\)</span> (describing gravitational radiation) are harmonic is refuted.</p></abstract><trans-abstract xml:lang="ru"><p style="text-align: justify;">Тензор кривизны <span class="math inline">\(\hat{R}\)</span> многообразия называется гармоничным, если он подчиняется условию <span class="math inline">\(\Delta^{\text{(HR)}}\hat{R}=0\)</span>, где <span class="math inline">\(\Delta^{\text{(HR)}}=DD^{\ast} +&#13;
D^{\ast}D\)</span> — лапласиан Ходжа-де Рама. Доказывается, что все решения уравнений Эйнштейна в пустоте, а также все решения теории Эйнштейна–Картана в пустоте обладают гармоничной кривизной. Опровергается утверждение о том, что гармоничными являются только решения уравнений Эйнштейна типа <span class="math inline">\(N\)</span>, описывающее гравитационное излучение.</p></trans-abstract><kwd-group xml:lang="en"><kwd>Hodge-de Rham Laplacian</kwd><kwd>harmonic curvature tensor</kwd><kwd>harmonic solutions in vacuum of Einstein equation and Einstein-Cartan theory equations</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>Лапласиан Ходжа-де Рама</kwd><kwd>гармоничный тензор кривизны</kwd><kwd>гармоничные решения в пустоте уравнений Эйнштейна и уравнений теории Эйнштейна-Картана</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>G. de Rham, Differentiable manifolds: forms, currents, harmonic forms. Berlin, Heidelberg, New York, Tokyo: Springer-Verlag, 2011, 180 pp.</mixed-citation></ref><ref id="B2"><label>2.</label><mixed-citation>M. O. Katanaev, “Geometric methods in mathematical physics,” in Russian. arXiv: 1311.0733v3[math-ph].</mixed-citation></ref><ref id="B3"><label>3.</label><mixed-citation>A. L. Besse, Einstein manifolds. Berlin, Heidelberg: Springer-Verlag, 1987.</mixed-citation></ref><ref id="B4"><label>4.</label><mixed-citation>J.-P. Bourguignon, “Global riemannian geometry,” in T. J. Willmore and N. J. Hitchin, Eds. New York: Ellis Horwood Lim., 1984, ch. Metric with harmonic curvature.</mixed-citation></ref><ref id="B5"><label>5.</label><mixed-citation>D. A. Popov, “To the theory of the Yang-Mills fields,” Theoretical and mathematical physics, vol. 24, no. 3, pp. 347-356, 1975, in Rusian.</mixed-citation></ref><ref id="B6"><label>6.</label><mixed-citation>V. D. Zakharov, Gravitational waves in Einstein’s theory of gravitation. Moscow: Nauka, 1972, 200 pp., in Rusian.</mixed-citation></ref><ref id="B7"><label>7.</label><mixed-citation>O. V. Babourova and B. N. Frolov, “On a harmonic property of the Einstein manifold curvature,” 1995. arXiv: gr-qc/9503045v1.</mixed-citation></ref><ref id="B8"><label>8.</label><mixed-citation>D. A. Popov and L. I. Dajhin, “Einstein spaces and Yang-Mills fields,” Reports of the USSR Academy of Sciences [Doklady Akademii nauk SSSR], vol. 225, no. 4, pp. 790-793, 1975.</mixed-citation></ref></ref-list></back></article>
