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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="en"><front><journal-meta><journal-id journal-id-type="publisher-id">najo</journal-id><journal-title-group><journal-title xml:lang="en">Nanosystems: Physics, Chemistry, Mathematics</journal-title><trans-title-group xml:lang="ru"><trans-title>Наносистемы: физика, химия, математика</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2220-8054</issn><issn pub-type="epub">2305-7971</issn><publisher><publisher-name>Университет ИТМО</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.17586/2220-8054-2021-12-2-135-141</article-id><article-id custom-type="elpub" pub-id-type="custom">najo-350</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="en"><subject>MATHEMATICS</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>МАТЕМАТИКА</subject></subj-group></article-categories><title-group><article-title>Non-compact perturbations of the spectrum of multipliers given with functions</article-title><trans-title-group xml:lang="ru"><trans-title>Некомпактные возмущения спектра заданных мультипликаторов с функциями</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>Kucharov</surname><given-names>R. R.</given-names></name><name name-style="western" xml:lang="en"><surname>Kucharov</surname><given-names>R. R.</given-names></name></name-alternatives><bio xml:lang="ru"><p>100174, Tashkent</p></bio><bio xml:lang="en"><p>100174, Tashkent</p></bio><email xlink:type="simple">ramz3364647@yahoo.com</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>Khamraeva</surname><given-names>R. R.</given-names></name><name name-style="western" xml:lang="en"><surname>Khamraeva</surname><given-names>R. R.</given-names></name></name-alternatives><bio xml:lang="ru"><p>100174, Tashkent,</p><p>100010, 12, Istiqbol str., Tashkent</p></bio><bio xml:lang="en"><p>100174, Tashkent,</p><p>100010, 12, Istiqbol str., Tashkent</p></bio><email xlink:type="simple">r.khamraeva@wiut.uz</email><xref ref-type="aff" rid="aff-2"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>National University of Uzbekistan</institution></aff><aff xml:lang="en"><institution>National University of Uzbekistan</institution></aff></aff-alternatives><aff-alternatives id="aff-2"><aff xml:lang="ru"><institution>National University of Uzbekistan;&#13;
Westminster International University in Tashkent</institution></aff><aff xml:lang="en"><institution>National University of Uzbekistan;&#13;
Westminster International University in Tashkent</institution></aff></aff-alternatives><pub-date pub-type="collection"><year>2021</year></pub-date><pub-date pub-type="epub"><day>28</day><month>07</month><year>2025</year></pub-date><volume>12</volume><issue>2</issue><fpage>135</fpage><lpage>141</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Kucharov R.R., Khamraeva R.R., 2025</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="ru">Kucharov R.R., Khamraeva R.R.</copyright-holder><copyright-holder xml:lang="en">Kucharov R.R., Khamraeva R.R.</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://nanojournal.ifmo.ru/jour/article/view/350">https://nanojournal.ifmo.ru/jour/article/view/350</self-uri><abstract><p>The change in the spectrum of the multipliers H0 f (x, y) = xa + yβ f (x, y) and H0 f (x, y) = xayβ f (x, y) for perturbation with partial integral operators in the spaces L2 [0, 1]2 is studied. Precise description of the essential spectrum and the existence of simple eigenvalue is received. We prove that the number of eigenvalues located below the lower edge of the essential spectrum in the model is finite.</p></abstract><trans-abstract xml:lang="ru"><p>Изучается изменение спектра множителей H0 f(x;y) = xα + yβ f(x;y) и H0 f(x;y) = xαyβ f(x;y) при возмущении операторами в частных интегралах в пространствах L2[0; 1]2. Получено точное описание существенного спектра и существование простого собственного значения. Доказано, что число собственных значений, расположенных ниже нижнего края существенного спектра в модели, конечно.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>существенный спектр</kwd><kwd>дискретный спектр</kwd><kwd>нижняя граница существенного спектра</kwd><kwd>оператор частного интеграла</kwd></kwd-group><kwd-group xml:lang="en"><kwd>essential spectrum</kwd><kwd>discrete spectrum</kwd><kwd>lower bound of the essential spectrum</kwd><kwd>partial integral operator</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Uchiyama J. Finiteness of the Number of Discrete Eigenvalues of the Schrodinger Operator for a Three Particle System. 1969, Publ. Res. Inst. Math. Sci., 5 (1), P. 51–63.</mixed-citation><mixed-citation xml:lang="en">Uchiyama J. Finiteness of the Number of Discrete Eigenvalues of the Schrodinger Operator for a Three Particle System. 1969, Publ. Res. Inst. Math. Sci., 5 (1), P. 51–63.</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Uchiyama J. Corrections to ”Finiteness of the Number of Discrete Eigenvalues of the Schrodinger Operator for a Three Particle System”. Publ. Res. Inst. Math. Sci., 1970, 6 (1), P. 189–192.</mixed-citation><mixed-citation xml:lang="en">Uchiyama J. Corrections to ”Finiteness of the Number of Discrete Eigenvalues of the Schrodinger Operator for a Three Particle System”. Publ. Res. Inst. Math. Sci., 1970, 6 (1), P. 189–192.</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Uchiyama J. Finiteness of the Number of Discrete Eigenvalues of the Schrodinger Operator for a Three Particle System. Publ. Res. Inst. Math. Sci., 1970, 6 (1), P. 193–200.</mixed-citation><mixed-citation xml:lang="en">Uchiyama J. Finiteness of the Number of Discrete Eigenvalues of the Schrodinger Operator for a Three Particle System. Publ. Res. Inst. Math. Sci., 1970, 6 (1), P. 193–200.</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Zhislin G.M. On the finiteness of the discrete spectrum of the energy operator of negative atomic and molecular ions. Theor. Math. Phys., 1971, 7, P. 571–578.</mixed-citation><mixed-citation xml:lang="en">Zhislin G.M. On the finiteness of the discrete spectrum of the energy operator of negative atomic and molecular ions. Theor. Math. Phys., 1971, 7, P. 571–578.</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Appell J., Frolova E.V., Kalitvin A.S., Zabrejko P.P. Partial integral operators on C(a, b. × c, d.). Integral Equ. Oper. theory, 1997, 27, P. 125–140.</mixed-citation><mixed-citation xml:lang="en">Appell J., Frolova E.V., Kalitvin A.S., Zabrejko P.P. Partial integral operators on C(a, b. × c, d.). Integral Equ. Oper. theory, 1997, 27, P. 125–140.</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Faddeev L.D. On a model of Friedrichs in the theory of perturbations of the continuous spectrum. Trudy Mat. Inst. Steklov, 1964, 73, 292 in Russian..</mixed-citation><mixed-citation xml:lang="en">Faddeev L.D. On a model of Friedrichs in the theory of perturbations of the continuous spectrum. Trudy Mat. Inst. Steklov, 1964, 73, 292 in Russian..</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Albeverio S., Lakaev S.N., Muminov Z.I. On the number of eigenvalues of a model operator associated to a system of three-particles on lattices. Russ. J. Math. Phys., 2007, 14 (4), P. 377—387.</mixed-citation><mixed-citation xml:lang="en">Albeverio S., Lakaev S.N., Muminov Z.I. On the number of eigenvalues of a model operator associated to a system of three-particles on lattices. Russ. J. Math. Phys., 2007, 14 (4), P. 377—387.</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Rasulov T.Kh. Asymptotics of the discrete spectrum of a model operator assotiated with a system of three particles on a lattice. Theor. and Math. Phys., 2010, 163 (1), P. 429–437.</mixed-citation><mixed-citation xml:lang="en">Rasulov T.Kh. Asymptotics of the discrete spectrum of a model operator assotiated with a system of three particles on a lattice. Theor. and Math. Phys., 2010, 163 (1), P. 429–437.</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh., Kucharov R.R. Essential and discrete spectra of the three-particle Schrodinger operator on a lattice. Theor. Math. Phys., 2012, 170 (3), P. 341-–353.</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh., Kucharov R.R. Essential and discrete spectra of the three-particle Schrodinger operator on a lattice. Theor. Math. Phys., 2012, 170 (3), P. 341-–353.</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh., Kucharov R.R. Efimov’s effect for partial integral operators of Fredholm type. Nanosystems: Physics, Chemistry, Mathematics, 2013, 4 (4), P. 529–537.</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh., Kucharov R.R. Efimov’s effect for partial integral operators of Fredholm type. Nanosystems: Physics, Chemistry, Mathematics, 2013, 4 (4), P. 529–537.</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh. On infinity of the discrete spectrum of operators in the Friedrichs model. Siberian Adv. Math., 2012, 22 (1).</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh. On infinity of the discrete spectrum of operators in the Friedrichs model. Siberian Adv. Math., 2012, 22 (1).</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Reed M., Simon B. Methods of Modern Mathematical Physics, Vol. 4, Analysis of Operators, Acad. Press, New York, 1982.</mixed-citation><mixed-citation xml:lang="en">Reed M., Simon B. Methods of Modern Mathematical Physics, Vol. 4, Analysis of Operators, Acad. Press, New York, 1982.</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh. Efimov’s effect for a 3-particle model discrete Schrodinger operator. Theor. Math. Phys., 2010, 164 (1), P. 896-–904.</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh. Efimov’s effect for a 3-particle model discrete Schrodinger operator. Theor. Math. Phys., 2010, 164 (1), P. 896-–904.</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh. On a discrete “three-particle” Schrodinger operator in the Hubbard model. Theor. Math. Phys., 2006, 149 (2), P. 1497–1511.</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh. On a discrete “three-particle” Schrodinger operator in the Hubbard model. Theor. Math. Phys., 2006, 149 (2), P. 1497–1511.</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>
