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<article article-type="research-article" dtd-version="1.3" 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" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">mathnas</journal-id><journal-title-group><journal-title xml:lang="ru">Труды Института математики НАН Беларуси</journal-title><trans-title-group xml:lang="en"><trans-title>Proceedings of the Institute of Mathematics of the NAS of Belarus</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">1812-5093</issn><publisher><publisher-name>Институт математики НАН Беларуси</publisher-name></publisher></journal-meta><article-meta><article-id custom-type="edn" pub-id-type="custom">HQZGXB</article-id><article-id custom-type="elpub" pub-id-type="custom">mathnas-95</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>АЛГЕБРА И ТЕОРИЯ ЧИСЕЛ</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>ALGEBRA AND NUMBER THEORY</subject></subj-group></article-categories><title-group><article-title>Об одной фундаментальной области в специальной линейной группе</article-title><trans-title-group xml:lang="en"><trans-title>On a fundamental domain in a special linear group</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Матвеев</surname><given-names>Г. В.</given-names></name><name name-style="western" xml:lang="en"><surname>Matveev</surname><given-names>G. V.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Минск</p></bio><bio xml:lang="en"><p>Minsk</p></bio><email xlink:type="simple">matveev@bsu.by</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Осиновская</surname><given-names>А. А.</given-names></name><name name-style="western" xml:lang="en"><surname>Osinovskaya</surname><given-names>A. A.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Минск</p></bio><bio xml:lang="en"><p>Minsk</p></bio><email xlink:type="simple">anna@im.bas-net.by</email><xref ref-type="aff" rid="aff-2"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Белорусский государственный университет</institution></aff><aff xml:lang="en"><institution>Belarusian State University</institution></aff></aff-alternatives><aff-alternatives id="aff-2"><aff xml:lang="ru"><institution>Институт математики НАН Беларуси</institution></aff><aff xml:lang="en"><institution>Institute of Mathematics of the National Academy of Sciences of Belarus</institution></aff></aff-alternatives><pub-date pub-type="collection"><year>2025</year></pub-date><pub-date pub-type="epub"><day>05</day><month>01</month><year>2026</year></pub-date><volume>33</volume><issue>2</issue><fpage>21</fpage><lpage>27</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Матвеев Г.В., Осиновская А.А., 2026</copyright-statement><copyright-year>2026</copyright-year><copyright-holder xml:lang="ru">Матвеев Г.В., Осиновская А.А.</copyright-holder><copyright-holder xml:lang="en">Matveev G.V., Osinovskaya A.A.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://mathnas.ejournal.by/jour/article/view/95">https://mathnas.ejournal.by/jour/article/view/95</self-uri><abstract><p>Модулярное разделение секрета в группе $SL_2(\mathbb{Z})$ было предложено Янчевским, Матвеевым и Говорушко. В настоящей работе построена в явном виде вся фундаментальная область при действии левыми сдвигами главной конгруэнц-подгруппы на группе $SL_2(\mathbb{Z})$, что представляет дополнительные возможности для построения схем, так как эта область является пространством хранимых секретов схемы разделения секрета.</p></abstract><trans-abstract xml:lang="en"><p>Modular secret sharing in the group $SL_2(\mathbb{Z})$ was recently proposed by Yanchevskiy, Matveev, and Govorushko. In this paper we have constructed in explicit form the entire fundamental domain under the action of left shifts of the principal congruence subgroup on the group $SL_2(\mathbb{Z})$, which presents additional possibilities for constructing schemes, since the domain is the space of stored secrets of the secret sharing scheme.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>специальная линейная группа</kwd><kwd>конгруэнц-подгруппа</kwd><kwd>фундаментальная область</kwd></kwd-group><kwd-group xml:lang="en"><kwd>special linear group</kwd><kwd>congruence subgroup</kwd><kwd>fundamental domain</kwd></kwd-group><funding-group><funding-statement xml:lang="ru">Работа выполнена при финансовой поддержке БРФФИ, договор № Ф25-012</funding-statement></funding-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Янчевский В. И., Говорушко И. О., Матвеев Г. В. Разделение секрета в специальной линейной группе // Информатика. 2024. Т. 21, № 3. С. 23–31. https://doi.org/10.37661/1816-0301-2024-21-3-23-31</mixed-citation><mixed-citation xml:lang="en">Yanchevskiy V. I., Govorushko I. O., Matveev G. V. Secret sharing in the special linear group. Informatics, 2024, vol. 21, no. 3, pp. 23–31 (in Russian). https://doi.org/10.37661/1816-0301-2024-21-3-23-31</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Harcos G. CEU lecture notes: a set of representatives for Γ0(q) SL2(Z) [Electronic resourse]. – Mode of access: https://users.renyi.hu/ĝHarcos/CEU_Gamma0(q).pdf</mixed-citation><mixed-citation xml:lang="en">Harcos G. CEU lecture notes: a set of representatives for Γ0(q) SL2(Z) [Electronic resourse]. – Mode of access: https://users.renyi.hu/ĝHarcos/CEU_Gamma0(q).pdf</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Платонов В. П., Рапинчук А. С. Алгебраические группы и теория чисел. M. : Наука, 1991. 656 с.</mixed-citation><mixed-citation xml:lang="en">Platonov V., Rapinchuk A. Algebraic groups and number theory. Pure and Applied Mathematics, 139. Boston, Academic Press Inc., 1994. xii+614 p.</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Матвеев Г. В., Осиновская А. А., Янчевский В. И. Фундаментальная область в специальной линейной группе SL2(Fp[x]) и схема разделения секрета на ее основе // Труды Института математики НАН Беларуси. 2024. Т. 32, № 2. С. 7–16.</mixed-citation><mixed-citation xml:lang="en">Di Matteo G. The action of SL2(Z) on the upper-half complex plane [Electronic resourse]. – Mode of access: https://www.dimatteo.is/Mathematics/Courses/Modular-forms/02-SL2Z.pdf</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Di Matteo G. The action of SL2(Z) on the upper-half complex plane[Electronic resourse]. – Mode of access: https://www.dimatteo.is/Mathematics/Courses/Modular-forms/02-SL2Z.pdf</mixed-citation><mixed-citation xml:lang="en">Matveev G. V., Osinovskaya A. A., Yanchevskii V. I. A fundamental domain in the special linear group and secret sharing on its basis. Proceedings of the Institute of Mathathematics of the NAS of Belarus, 2024, vol. 32, no. 2, pp. 23–31 (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Mignotte M. How to share a secret // Lecture Notes in Computer Science. 1983. Vol. 149. P. 371–375.</mixed-citation><mixed-citation xml:lang="en">Mignotte M. How to share a secret. Lecture Notes in Computer Science, 1983, vol. 149, pp. 371–375.</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
