<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.3 20210610//EN" "JATS-journalpublishing1-3.dtd">
<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">10.17586/22208054201785553558</article-id><article-id custom-type="elpub" pub-id-type="custom">najo-593</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>Lyapunov operator L with degenerate kernel and Gibbs measures</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>Kashkadarya</p></bio><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><xref ref-type="aff" rid="aff-2"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="en">Karshi State University<country>Uzbekistan</country></aff></aff-alternatives><aff-alternatives id="aff-2"><aff xml:lang="en">National University of Uzbekistan<country>Uzbekistan</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2017</year></pub-date><pub-date pub-type="epub"><day>12</day><month>08</month><year>2025</year></pub-date><volume>8</volume><issue>5</issue><elocation-id>553–558</elocation-id><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 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/593">https://nanojournal.ifmo.ru/jour/article/view/593</self-uri><abstract><p>In this paper, we studied the fixed points of the Lyapunov operator with degenerate kernel, in which each fixed point of the operator is corresponds to a translationinvariant Gibbs measure with four competing interactions of models with uncountable set of spin values on the Cayley tree of order two. Also, it was proved that Lyapunov operator with degenerate kernel has at most three positive fixed points.</p></abstract><kwd-group xml:lang="en"><kwd>Cayley tree</kwd><kwd>Gibbs measure</kwd><kwd>translationinvariant Gibbs measure</kwd><kwd>Lyupanov operator</kwd><kwd>degenerate kernel</kwd><kwd>fixed point</kwd></kwd-group><funding-group xml:lang="en"><funding-statement>We thank the referee for their careful reading of the manuscript and useful comments.</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">Georgii H.O. Gibbs measures and phase transitions. Second edition. de Gruyter Studies in Mathematics, 9. Walter de Gruyter, Berlin, 2011.</mixed-citation><mixed-citation xml:lang="en">Georgii H.O. Gibbs measures and phase transitions. Second edition. de Gruyter Studies in Mathematics, 9. Walter de Gruyter, Berlin, 2011.</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Preston C. Gibbs states on countable sets. Cambridge University Press, London, 1974.</mixed-citation><mixed-citation xml:lang="en">Preston C. Gibbs states on countable sets. Cambridge University Press, London, 1974.</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Monroe J.L. Phase diagrams od Ising models on Husime trees two. J.Statist.Phys., 1992, 67, P. 1185–2000.</mixed-citation><mixed-citation xml:lang="en">Monroe J.L. Phase diagrams od Ising models on Husime trees two. J.Statist.Phys., 1992, 67, P. 1185–2000.</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Monroe J.L. A new criterion for the location of phase transitions for spin system on a recursive lattice. Phys.Lett.A., 1994, 188, P. 80–84.</mixed-citation><mixed-citation xml:lang="en">Monroe J.L. A new criterion for the location of phase transitions for spin system on a recursive lattice. Phys.Lett.A., 1994, 188, P. 80–84.</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Mukhamedov F.M., Rozikov U.A. On Gibbs measures of models with completing ternary and binary interactions and corresponding von Neumann algebras. J.Statist.Phys., 2004, 114, P. 825–848.</mixed-citation><mixed-citation xml:lang="en">Mukhamedov F.M., Rozikov U.A. On Gibbs measures of models with completing ternary and binary interactions and corresponding von Neumann algebras. J.Statist.Phys., 2004, 114, P. 825–848.</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Ganikhodjaev N.N., Pah C.H., Wahiddin M.R.B. An Ising model with three competing interactions on a Cayley tree. J. Math. Phys., 2004, 45, P. 3645–3658.</mixed-citation><mixed-citation xml:lang="en">Ganikhodjaev N.N., Pah C.H., Wahiddin M.R.B. An Ising model with three competing interactions on a Cayley tree. J. Math. Phys., 2004, 45, P. 3645–3658.</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Ganikhodjaev N.N., Rozikov U.A. On Ising model with four competing interactions on Cayley tree. Math. Phys. Anal. Geom., 2009, 12, P. 141–156.</mixed-citation><mixed-citation xml:lang="en">Ganikhodjaev N.N., Rozikov U.A. On Ising model with four competing interactions on Cayley tree. Math. Phys. Anal. Geom., 2009, 12, P. 141–156.</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Utkir A. Rozikov. Gibbs measures on a Cayley trees. World Sci. Pub., Singapore, 2013.</mixed-citation><mixed-citation xml:lang="en">Utkir A. Rozikov. Gibbs measures on a Cayley trees. World Sci. Pub., Singapore, 2013.</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Ganikhodjaev N.N., Rozikov U.A. The Potts model with countable set of spin values on a Cayley Tree. Letters Math. Phys., 2006, 75, P. 99–109.</mixed-citation><mixed-citation xml:lang="en">Ganikhodjaev N.N., Rozikov U.A. The Potts model with countable set of spin values on a Cayley Tree. Letters Math. Phys., 2006, 75, P. 99–109.</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh., Haydarov F.H., Rozikov U.A. Uniqueness of Gibbs Measure for Models With Uncountable Set of Spin Values on a Cayley Tree. Math. Phys. Anal. Geom., 2013, 16(1), P. 1–17.</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh., Haydarov F.H., Rozikov U.A. Uniqueness of Gibbs Measure for Models With Uncountable Set of Spin Values on a Cayley Tree. Math. Phys. Anal. Geom., 2013, 16(1), P. 1–17.</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh., Haydarov F.H., Rozikov U.A. Nonuniqueness of Gibbs Measure for Models With Uncountable Set of Spin Values on a Cayley Tree. J. Stat. Phys., 2012, 147, P. 779–794.</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh., Haydarov F.H., Rozikov U.A. Nonuniqueness of Gibbs Measure for Models With Uncountable Set of Spin Values on a Cayley Tree. J. Stat. Phys., 2012, 147, P. 779–794.</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Eshkabilov Yu.Kh., Haydarov F.H. On positive solutions of the homogenous Hammerstein integral equation. Nanosystems: Physics, Chemistry, Mathematics, 2015, 6(5), P. 618–627.</mixed-citation><mixed-citation xml:lang="en">Eshkabilov Yu.Kh., Haydarov F.H. On positive solutions of the homogenous Hammerstein integral equation. Nanosystems: Physics, Chemistry, Mathematics, 2015, 6(5), P. 618–627.</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Rozikov U.A., Haydarov F.H. Periodic Gibbs measures for models with uncountable set of spin values on a Cayley tree. Inf.Dim.Anal.Quan.Prob., 2015, 18, P. 1–22.</mixed-citation><mixed-citation xml:lang="en">Rozikov U.A., Haydarov F.H. Periodic Gibbs measures for models with uncountable set of spin values on a Cayley tree. Inf.Dim.Anal.Quan.Prob., 2015, 18, P. 1–22.</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Rozikov U.A., Haydarov F.H. Four competing interactions for models with an uncountable set of spin values on a Cayley tree. Theor. Math. Phys., 2017, 191(2), P. 748–761.</mixed-citation><mixed-citation xml:lang="en">Rozikov U.A., Haydarov F.H. Four competing interactions for models with an uncountable set of spin values on a Cayley tree. Theor. Math. Phys., 2017, 191(2), P. 748–761.</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Krasnosel’ski M.A. Positive solutions of opertor equations. Gos. Izd., Moscow, 1969 (in Russian).</mixed-citation><mixed-citation xml:lang="en">Krasnosel’ski M.A. Positive solutions of opertor equations. Gos. Izd., Moscow, 1969 (in Russian).</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>
