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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">10.17586/2220-8054-2015-6-5-618-627</article-id><article-id custom-type="elpub" pub-id-type="custom">najo-977</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>On positive solutions of the homogeneous Hammerstein integral equation</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>Haydarov</surname><given-names>F. H.</given-names></name></name-alternatives><bio xml:lang="en"><p>Tashkent</p></bio><email xlink:type="simple">haydarov_imc@mail.ru</email><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff xml:lang="en" id="aff-1"><institution>National University of Uzbekistan</institution><country>Uzbekistan</country></aff><pub-date pub-type="collection"><year>2015</year></pub-date><pub-date pub-type="epub"><day>15</day><month>08</month><year>2025</year></pub-date><volume>6</volume><issue>5</issue><fpage>618</fpage><lpage>627</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Eshkabilov Y.K., Haydarov F.H., 2025</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="ru">Eshkabilov Y.K., Haydarov F.H.</copyright-holder><copyright-holder xml:lang="en">Eshkabilov Y.K., Haydarov F.H.</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/977">https://nanojournal.ifmo.ru/jour/article/view/977</self-uri><abstract><p>In this paper the existence and uniqueness of positive fixed points operator for a nonlinear integral operator are discussed. We prove the existence of a finite number of positive solutions for the Hammerstein type of integral equation. Obtained results are applied to the study of Gibbs measures for models on a Cayley tree. </p></abstract><kwd-group xml:lang="en"><kwd>integral equation of Hammerstein type</kwd><kwd>fixed point of operator</kwd><kwd>Gibbs measure</kwd><kwd>Cayley tree</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">M.A. Abdou, A.A. Badr. On a method for solving an integral equation in the displacement contact problem. J. Appl. Math Comput., 2002, 127, P. 65–78.</mixed-citation><mixed-citation xml:lang="en">M.A. Abdou, A.A. Badr. On a method for solving an integral equation in the displacement contact problem. J. Appl. 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