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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">33496</article-id><article-id pub-id-type="doi">10.22363/2413-3639-2022-68-4-653-670</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">Explicit solution of a Dirichlet problem in nonconvex angle</article-title><trans-title-group xml:lang="ru"><trans-title>Явное решение задачи Дирихле в невыпуклом угле</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Merzon</surname><given-names>A.</given-names></name><name xml:lang="ru"><surname>Мерзон</surname><given-names>А.</given-names></name></name-alternatives><email>anatolimx@gmail.com</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Zhevandrov</surname><given-names>P.</given-names></name><name xml:lang="ru"><surname>Жевандров</surname><given-names>П.</given-names></name></name-alternatives><email>pzhevand@gmail.com</email><xref ref-type="aff" rid="aff2"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>De la Paz Méndez</surname><given-names>J. E.</given-names></name><name xml:lang="ru"><surname>Де ла Пас Мендес</surname><given-names>Х. Э.</given-names></name></name-alternatives><email>jeligio12@gmail.com</email><xref ref-type="aff" rid="aff3"/></contrib><contrib contrib-type="author"><name-alternatives><name xml:lang="en"><surname>Romero Rodriguez</surname><given-names>M. I.</given-names></name><name xml:lang="ru"><surname>Ромеро Родригес</surname><given-names>М. И.</given-names></name></name-alternatives><email>maria.romeror@unimilitar.edu.co</email><xref ref-type="aff" rid="aff4"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Instituto de Fiısica y Matemáticas, UMSNH</institution></aff><aff><institution xml:lang="ru">Instituto de Fisica y Matemáticas, UMSNH</institution></aff></aff-alternatives><aff id="aff2"><institution>Facultad de Ciencias Fisico-Matemáticas, UMSNH</institution></aff><aff-alternatives id="aff3"><aff><institution xml:lang="en">Escuela Superior de Matemáticas N.2, UAGro, Cd</institution></aff><aff><institution xml:lang="ru">Escuela Superior de Matemáticas N.2, UAGro</institution></aff></aff-alternatives><aff id="aff4"><institution>Facultad de Ciencias Básicas y Aplicadas, Universidad Militar Nueva Granada</institution></aff><pub-date date-type="pub" iso-8601-date="2022-12-15" publication-format="electronic"><day>15</day><month>12</month><year>2022</year></pub-date><volume>68</volume><issue>4</issue><issue-title xml:lang="en">VOL 68, NO4 (2022)</issue-title><issue-title xml:lang="ru">ТОМ 68, №4 (2022)</issue-title><fpage>653</fpage><lpage>670</lpage><history><date date-type="received" iso-8601-date="2023-02-06"><day>06</day><month>02</month><year>2023</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2022, Merzon A., Zhevandrov P., De la Paz Méndez J.E., Romero Rodriguez M.I.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2022, Мерзон А., Жевандров П., Де ла Пас Мендес Х.Э., Ромеро Родригес М.И.</copyright-statement><copyright-year>2022</copyright-year><copyright-holder xml:lang="en">Merzon A., Zhevandrov P., De la Paz Méndez J.E., Romero Rodriguez M.I.</copyright-holder><copyright-holder xml:lang="ru">Мерзон А., Жевандров П., Де ла Пас Мендес Х.Э., Ромеро Родригес М.И.</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/CMFD/article/view/33496">https://journals.rudn.ru/CMFD/article/view/33496</self-uri><abstract xml:lang="en"><p style="text-align: justify;">In the present work, we give an explicit solution of the Dirichlet boundary-value problem for the Helmholtz equation in a nonconvex angle with periodic boundary data. We present uniqueness and existence theorems in an appropriate functional class and we give an explicit formula for the solution in the form of the Sommerfeld integral. The method of complex characteristics [14] is used.</p></abstract><trans-abstract xml:lang="ru"><p style="text-align: justify;">В этой работе мы даем явное решение краевой задачи Дирихле для уравнения Гельмгольца в невыпуклом угле с периодическими граничными данными. Мы представляем теоремы единственности и существования в соответствующем функциональном классе и даем явную формулу решения в виде интеграла Зоммерфельда. Используется метод комплексных характеристик [14].</p></trans-abstract><kwd-group xml:lang="en"><kwd>Helmholtz equation</kwd><kwd>nonconvex angle</kwd><kwd>Sommerfeld integral</kwd><kwd>method of complex characteristics</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>уравнение Гельмгольца</kwd><kwd>невыпуклый угол</kwd><kwd>интеграл Зоммерфельда</kwd><kwd>метод комплексных характеристик</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Малышев В. А. Случайные блуждания. Уравнения Винера-Хопфа в четверти плоскости. Автоморфизмы Галуа. - М.: МГУ, 1970.</mixed-citation></ref><ref id="B2"><label>2.</label><mixed-citation>Babich V. M., Lyalinov M. A., Grikurov V. E. Di raction theory: The Sommerfeld-Malyuzhinets Technique. - Oxford: Alpha Science, 2008.</mixed-citation></ref><ref id="B3"><label>3.</label><mixed-citation>Castro L. P., Kapanadze D. Dirichlet-Neumann impedance boundary-value problems arising in rectangular wedge di raction problems// Proc. Am. Math. Soc. - 2008. - 136. - C. 2113-2123.</mixed-citation></ref><ref id="B4"><label>4.</label><mixed-citation>Castro L. P., Kapanadze D. Wave di raction by a 45 degree wedge sector with Dirichlet and Neumann boundary conditions// Math. Comput. Modelling. - 2008. - 48, № 1/2. - C. 114-121.</mixed-citation></ref><ref id="B5"><label>5.</label><mixed-citation>Castro L. P., Kapanadze D. Wave di raction by a 270 degrees wedge sector with Dirichlet, Neumann and impedance boundary conditions// Proc. A. Razmadze Math. Inst. - 2011. - 155. - C. 96-99.</mixed-citation></ref><ref id="B6"><label>6.</label><mixed-citation>Castro L. P., Speck F.-O., Teixeira F. S. On a class of wedge di raction problems posted by Erhard Meister// Oper. Theory Adv. Appl. - 2004. - 147. - C. 213-240.</mixed-citation></ref><ref id="B7"><label>7.</label><mixed-citation>Castro L. P., Speck F.-O., Teixeira F. S. Mixed boundary value problems for the Helmholtz equation in a quadrant// Integral Equ. Oper. Theory. - 2006. - 56. - C. 1-44.</mixed-citation></ref><ref id="B8"><label>8.</label><mixed-citation>Croisille J.-P., Lebeau G. Di raction by an elastic immersed wedge. - Berlin-Heidelberg: Springer, 1999.</mixed-citation></ref><ref id="B9"><label>9.</label><mixed-citation>Kay I. The di raction of an arbitrary pulse by a wedge// Commun. Pure Appl. Math. - 1953. - 6.- C. 521-546.</mixed-citation></ref><ref id="B10"><label>10.</label><mixed-citation>Komech A. I. Elliptic boundary value problems on manifolds with piecewise smooth boundary// Math. USSR Sb. - 1973. - 21. - C. 91-135.</mixed-citation></ref><ref id="B11"><label>11.</label><mixed-citation>Merzon A. E., De la Paz M´endez J. E. DN-scattering of a plane wave by wedges// Math. Methods Appl. Sci. - 2011. - 34, № 15. - C. 1843-1872.</mixed-citation></ref><ref id="B12"><label>12.</label><mixed-citation>Komech A. I., Mauser N. J., Merzon A. E. On Sommerfeld representation and uniqueness in scattering by wedges// Math. Methods Appl. Sci. - 2004. - 28. - C. 147-183.</mixed-citation></ref><ref id="B13"><label>13.</label><mixed-citation>Komech A. I., Merzon A. E. Limiting amplitude principle in the scattering by wedges// Math. Methods Appl. Sci. - 2006. - 29, № 10. - C. 1147-1185.</mixed-citation></ref><ref id="B14"><label>14.</label><mixed-citation>Komech A., Merzon A. Stationary di raction by wedges. - Cham: Springer, 2019.</mixed-citation></ref><ref id="B15"><label>15.</label><mixed-citation>Komech A. I., Merzon A. E., De la Paz M´endez J. E. On uniqueness and stability of Sobolev’s solution in scattering by wedges// Z. Angew. Math. Phys. - 2015. - 66, № 5. - C. 2485-2498.</mixed-citation></ref><ref id="B16"><label>16.</label><mixed-citation>Komech A. I., Merzon A. E., Esquivel Navarrete A., De la Paz M´endez J. E., Villalba Vega T. J. Sommerfeld’s solution as the limiting amplitude and asymptotics for narrow wedges// Math. Methods Appl. Sci. - 2018. - 42. - C. 4957-4970.</mixed-citation></ref><ref id="B17"><label>17.</label><mixed-citation>Komech A. I., Merzon A. E., De la Paz M´endez J. E. Time-dependent scattering of generalized plane waves by wedges// Math. Methods Appl. Sci. - 2015. - 38, № 18. - C. 4774-4785.</mixed-citation></ref><ref id="B18"><label>18.</label><mixed-citation>Meister E. Some solved and unsolved canonical problems of di raction theory// В сб.: «Di er. Equ. Math. Phys. Proc. Int. Conf., Birmingham, USA, March 3-8, 1986». - Berlin etc.: Springer, 1987. - С. 320-336.</mixed-citation></ref><ref id="B19"><label>19.</label><mixed-citation>Meister E., Passow A., Rottbrand K. New results on wave di raction by canonical obstacles// Oper. Theory Adv. Appl. - 1999. - 110. - C. 235-256.</mixed-citation></ref><ref id="B20"><label>20.</label><mixed-citation>Meister E., Penzel F., Speck F.-O., Teixeira F. S. Some interior and exterior boundary-value problems for the Helmholtz equations in a quadrant// Proc. Roy. Soc. Edinburgh Sect. A. - 1993. - 123, № 2. - C. 275-294.</mixed-citation></ref><ref id="B21"><label>21.</label><mixed-citation>Meister E., Penzel F., Speck F.-O., Teixeira F. S. Two canonical wedge problems for the Helmholtz equation// Math. Methods Appl. Sci. - 1994. - 17. - C. 877-899.</mixed-citation></ref><ref id="B22"><label>22.</label><mixed-citation>Meister E., Speck F.-O., Teixeira F. S. Wiener-Hopf-Hankel operators for some wedge di raction problems with mixed boundary conditions// J. Integral Equ. Appl. - 1992. - 4, № 2. - C. 229-255.</mixed-citation></ref><ref id="B23"><label>23.</label><mixed-citation>Merzon A. E., Komech A. I., De la Paz M´endez J. E., Villalba T. J. On the Keller-Blank solution to the scattering problem of pulses by wedges// Math. Methods Appl. Sci. - 2015. - 38, № 10. - C. 2035-2040.</mixed-citation></ref><ref id="B24"><label>24.</label><mixed-citation>Merzon A. E., Zhevandrov P. N., De la Paz M´endez J. E. On the behavior of the edge di racted nonstationary wave in scattering by wedges near the front// Russ. J. Math. Phys. - 2015. - 22, № 4. - C. 491-503.</mixed-citation></ref><ref id="B25"><label>25.</label><mixed-citation>Muskhelishvili N. I. Singular integral equations. - Dordrecht: Springer, 1958.</mixed-citation></ref><ref id="B26"><label>26.</label><mixed-citation>Penzel F., Teixeira F. S. The Helmholtz equation in a quadrant with Robin’s conditions// Math. Methods Appl. Sci. - 1999. - 22. - C. 201-216.</mixed-citation></ref><ref id="B27"><label>27.</label><mixed-citation>Reed M., Simon B. Methods of modern mathematical physics II: Fourier analysis, self-adjointness. - New York: Academic Press, 1975.</mixed-citation></ref><ref id="B28"><label>28.</label><mixed-citation>Sommerfeld A. Mathematical theory of di raction. - Boston: Birkha¨user, 2004.</mixed-citation></ref></ref-list></back></article>
