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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 custom-type="elpub" pub-id-type="custom">najo-1217</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>CONTRIBUTED TALKS</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>CONTRIBUTED TALKS</subject></subj-group></article-categories><title-group><article-title>Efimov’s effect for partial integral operators of Fredholm type</article-title><trans-title-group xml:lang="ru"><trans-title></trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Eshkabilov</surname><given-names>Yu. Kh.</given-names></name></name-alternatives><bio xml:lang="en"><p> Tashkent</p></bio><email xlink:type="simple">yusup62@mail.ru</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Kucharov</surname><given-names>R. R.</given-names></name></name-alternatives><bio xml:lang="en"><p> Tashkent</p></bio><email xlink:type="simple">ramz3364647@yahoo.com</email><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="en">Department of Mechanics and Mathematics, National University of Uzbekistan<country>Uzbekistan</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2013</year></pub-date><pub-date pub-type="epub"><day>20</day><month>08</month><year>2025</year></pub-date><volume>4</volume><issue>4</issue><issue-title>Special Issue.  INTERNATIONAL CONFERENCE   "MATHEMATICAL CHALLENGE OF QUANTUM  TRANSPORT IN NANOSYSTEMS - 2013.   PIERRE DUCLOS WORKSHOP"</issue-title><fpage>529</fpage><lpage>537</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Eshkabilov Y.K., Kucharov R.R., 2025</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="ru">Eshkabilov Y.K., Kucharov R.R.</copyright-holder><copyright-holder xml:lang="en">Eshkabilov Y.K., Kucharov R.R.</copyright-holder><license 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/1217">https://nanojournal.ifmo.ru/jour/article/view/1217</self-uri><abstract><p>We study the existence of an infinite number of eigenvalues (the existence of Efimov’s effect) for a self-adjoint partial integral operators. We prove a theorem on the necessary and sufficient conditions for the existence of Efimov’s effect for the Fredholm type partial integral operators.</p></abstract><kwd-group xml:lang="en"><kwd>essential spectrum</kwd><kwd>discrete spectrum</kwd><kwd>Efimov’s effect</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">Kalitvin A.S.On partial integral operators incontact problems of elasticity. (in Russian) Proc. 26 Voronezh Winter School, 54, (1994).</mixed-citation><mixed-citation xml:lang="en">Kalitvin A.S.On partial integral operators incontact problems of elasticity. (in Russian) Proc. 26 Voronezh Winter School, 54, (1994).</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Kovalenko E.V. 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