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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">Contemporary Mathematics. Fundamental Directions</journal-id><journal-title-group><journal-title xml:lang="en">Contemporary Mathematics. Fundamental Directions</journal-title><trans-title-group xml:lang="ru"><trans-title>Современная математика. Фундаментальные направления</trans-title></trans-title-group></journal-title-group><issn publication-format="print">2413-3639</issn><issn publication-format="electronic">2949-0618</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">23054</article-id><article-id pub-id-type="doi">10.22363/2413-3639-2019-65-4-623-634</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>New Results</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>Новые результаты</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">Application of Contemporary Proof of the Sforza Formula to Computation of Volumes of Hyperbolic Tetrahedra of Special Kind</article-title><trans-title-group xml:lang="ru"><trans-title>О применении современного доказательства формулы Сфорца к вычислению объемов гиперболических тетраэдров специального вида</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Krasnov</surname><given-names>V. A.</given-names></name><name xml:lang="ru"><surname>Краснов</surname><given-names>В. А.</given-names></name></name-alternatives><email>krasnov_va@rudn.university</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Peoples’ Friendship University of Russia (RUDN University)</institution></aff><aff><institution xml:lang="ru">Российский университет дружбы народов</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>65</volume><issue>4</issue><issue-title xml:lang="en">Proceedings of the S.M. Nikolskii Mathematical Institute of RUDN University</issue-title><issue-title xml:lang="ru">Труды Математического института им. С.М. Никольского РУДН</issue-title><fpage>623</fpage><lpage>634</lpage><history><date date-type="received" iso-8601-date="2020-03-02"><day>02</day><month>03</month><year>2020</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2020, Contemporary Mathematics. Fundamental Directions</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2020, Современная математика. Фундаментальные направления</copyright-statement><copyright-year>2020</copyright-year><copyright-holder xml:lang="en">Contemporary Mathematics. Fundamental Directions</copyright-holder><copyright-holder xml:lang="ru">Современная математика. Фундаментальные направления</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/></permissions><self-uri xlink:href="https://journals.rudn.ru/CMFD/article/view/23054">https://journals.rudn.ru/CMFD/article/view/23054</self-uri><abstract xml:lang="en"><p>In this paper, we use the contemporary proof (by Abrosimov and Mednykh) of the Sforza formula for volume of an arbitrary non-Euclidean tetrahedron to derive new formulas that express volumes of hyperbolic tetrahedra of special kind (orthoschemes and tetrahedra with the symmetry group S 4) via dihedral angles.</p></abstract><trans-abstract xml:lang="ru"><p>В настоящей работе мы, используя современное доказательство формулы Сфорца объема произвольного неевклидова тетраэдра, предложенное Н.В. Абросимовым и А.Д. Медных, выведем новые формулы, выражающие объемы гиперболических тетраэдров специального вида (ортосхемы и тетраэдры с группой симметрии S 4) через двугранные углы.</p></trans-abstract><funding-group><funding-statement xml:lang="ru">Публикация подготовлена при поддержке Программы РУДН «5-100».</funding-statement></funding-group></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Абросимов Н.В., Выонг Хыу Б. Объем гиперболического тетраэдра с группой симметрий S4// Тр. Ин-та мат. и мех. УрО РАН. - 2017. -23, № 4. - С. 7-17.</mixed-citation></ref><ref id="B2"><label>2.</label><mixed-citation>Винберг Э.Б. Объемы неевклидовых многогранников// Усп. мат. наук. - 1993. -48, № 2. - С. 17-46.</mixed-citation></ref><ref id="B3"><label>3.</label><mixed-citation>Лобачевский Н.И. Воображаемая геометрия// В сб.: «Полное собр. соч. Т. 3». - M.-Л., 1949.</mixed-citation></ref><ref id="B4"><label>4.</label><mixed-citation>Abrosimov N.V., Mednykh A.D. 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