<?xml version="1.0" encoding="UTF-8"?>
<article article-type="research-article" dtd-version="1.1" 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">
  <front>
    <journal-meta>
      <issn publication-format="print">1683-3414</issn>
      <issn publication-format="electronic">1814-0807</issn>
      <journal-title-group>
        <journal-title>Владикавказский математический журнал</journal-title>
        <trans-title-group xml:lang="en">
          <trans-title>Vladikavkaz Mathematical Journal</trans-title>
        </trans-title-group>
      </journal-title-group>
      <publisher>
        <publisher-name>Южный математический институт - филиал Федерального государственного бюджетного учреждения науки Федерального научного центра «Владикавказский научный центр Российской академии наук» (ЮМИ ВНЦ РАН)</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Stoilow Factorization of the Heisenberg Group</article-title>
      </title-group>
      <trans-title-group xml:lang="ru">
        <trans-title>Факторизация Стоилова на группе Гейзенберга</trans-title>
      </trans-title-group>
      <article-id pub-id-type="doi">10.46698/o8833-7719-4418-f</article-id>
      <article-id pub-id-type="publisher-id">17180</article-id>
      <pub-date publication-format="electronic" date-type="pub">
        <month>09</month>
        <year>2025</year>
      </pub-date>
      <volume>27</volume>
      <issue>3</issue>
      <fpage>50</fpage>
      <lpage>59</lpage>
      <self-uri xlink:href="https://vmj.ru/eng/archive/detail.php?ELEMENT_ID=17229&amp;SECTION_ID=636">https://vmj.ru/eng/archive/detail.php?ELEMENT_ID=17229&amp;SECTION_ID=636</self-uri>
      <contrib-group>
        <contrib contrib-type="author">
          <name-alternatives>
            <name xml:lang="ru">
              <surname>Дорохин</surname>
              <given-names>Д. К.</given-names>
            </name>
            <name xml:lang="en">
              <surname>Dorokhin</surname>
              <given-names>D. K.</given-names>
            </name>
          </name-alternatives>
          <email>d.dorokhin@g.nsu.ru</email>
          <xref ref-type="aff" rid="aff1"/>
        </contrib>
      </contrib-group>
      <aff-alternatives id="aff1">
        <aff xml:lang="ru">Новосибирский государственный университет, Россия, 630090, Новосибирск, ул. Пирогова, 1</aff>
        <aff xml:lang="en">Novosibirsk State University, 1 Pirogov St., Novosibirsk 630090, Russia</aff>
      </aff-alternatives>
      <abstract>In this article we study the properties of quasiconformal mappings on the Heisenberg group \(\Bbb H^1\) and consider the definition of quasiconformal mappings in terms of the Beltrami equation. In particular, we obtain an explicit expression for the Beltrami coefficient for the composition of two quasiconformal mappings and we prove an analogue of the Stoilow factorization theorem on the plane. Namely, if the Beltrami coefficients of two quasiconformal mappings are equal almost everywhere, then there exists a conformal mapping such that by acting on one of the given quasiconformal mappings from the left, we obtain another given mapping. As an application of these results on the Heisenberg group \(\Bbb H^1\) we compute the Beltrami coefficients of some quasiconformal mappings and we prove a theorem on the images of quasi-Brownian motions. In specific examples we demonstrate the invariance of the Beltrami coefficient under the action of the composition of a conformal function on the corresponding left mapping. Using the Stoilow factorization on the Heisenberg group, we show that if two quasi-Brownian motions have the corresponding Beltrami coefficients equal almost everywhere, then their trajectories are equivalent only if the conformal map in the Stoilov factorization is a map obtained from a composition of translations, rotations and dilations.</abstract>
      <trans-abstract xml:lang="ru">В данной статье мы исследуем свойства квазиконформных отображений на группе Гейзенберга \(\Bbb H^1\) и рассматриваем определение квазиконформных отображений через уравнение Бельтрами. В частности, получено явное выражение коэффициента Бельтрами для композиции двух квазиконформных отображений и доказан аналог факторизационной теоремы Cтоилова на плоскости. А именно, если коэффициенты Бельтрами двух квазиконформных отображений почти всюду равны, то существует конформное отображение такое, что подействовав им слева на какой-то из данных квазиконформных отображений, мы получим другое заданное отображение. В качестве применения полученных результатов на группе Гейзенберга \(\Bbb H^1\) вычислены коэффициенты Бельтрами некоторых квазиконформных отображений, и доказана теорема об образах квазиброуновских движений. В конкретных примерах мы демонстрируем инвариантность коэффициента Бельтрами под действием на соответствующее отображение слева композицией конформной функции. С помощью доказанной факторизации Стоилова на группе Гейзенберга, мы показали, что если у двух квазиброуновских движений их соответствующие коэффициенты Бельтрами равны почти всюду, то их траектории эквивалентны только в случае, если конформное отображение в факторизации Стоилова есть отображение, полученное из композиции сдвигов, поворотов и растяжений.</trans-abstract>
      <kwd-group xml:lang="ru">
        <kwd>группа Гейзенберга</kwd>
        <kwd>факторизация Стоилова</kwd>
        <kwd>квазиконформные отображения</kwd>
        <kwd>система Бельтрами</kwd>
        <kwd>броуновское движение</kwd>
      </kwd-group>
      <kwd-group xml:lang="en">
        <kwd>Heisenberg group</kwd>
        <kwd>Stoilow factorization</kwd>
        <kwd>quasiconformal mappings</kwd>
        <kwd>Beltrami system</kwd>
        <kwd>Brownian motion</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <back>
    <ref-list>
      <ref id="R1">
        <label>1</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Astala, K., Iwaniec, T. and Martin, G.  Elliptic Partial Differential Equations and Quasiconformal Mappings in the Plane, Princeton, Princeton University Press, 2009, 696 p. DOI: 10.1515/ 9781400830114.</mixed-citation>
          <mixed-citation xml:lang="en">Astala, K., Iwaniec, T. and Martin, G. Elliptic Partial Differential Equations and Quasiconformal  Mappings in the Plane, Princeton, Princeton University Press, 2009, 696 p. DOI: 10.1515/ 9781400830114.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R2">
        <label>2</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Stoilow, S. Lecons Sur les Principes Topologiques de la Theorie des Fonctions Analytiques Professees a la Sorbonne et a l'Universite de Cernauti,Paris, Gauthier-Villars, 1938.</mixed-citation>
          <mixed-citation xml:lang="en">Stoilow, S. Lecons Sur les Principes Topologiques de la Theorie des Fonctions  Analytiques Professees a la Sorbonne et a l'Universite de Cernauti, Paris, Gauthier-Villars, 1938.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R3">
        <label>3</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Reshetnyak, Y. G. Space Mappings with Bounded Distortion,Siberian Mathematical Journal, 1967, vol. 8, pp. 466-487. DOI: 10.1007/BF02196429.</mixed-citation>
          <mixed-citation xml:lang="en">Reshetnyak, Y. G. Space Mappings with Bounded Distortion, Siberian Mathematical Journal, 1967, vol. 8, pp. 466-487. DOI: 10.1007/BF02196429.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R4">
        <label>4</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Mostow, G. D. Strong Rigidity of Locally Symmetric Spaces,Princeton University Press, 1973, 204 p.</mixed-citation>
          <mixed-citation xml:lang="en">Mostow, G. D. Strong Rigidity of Locally Symmetric Spaces, Princeton University Press, 1973, 204 p.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R5">
        <label>5</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Mostow, G. D. Quasi-Conformal Mappings in $n$-Spaces and the Rigidity of HyperbolicSpace Forms, Publications Mathematiques de l'Institut des Hautes Scientifiques,1968, vol. 34, pp. 53-104. DOI: 10.1007/BF02684590.</mixed-citation>
          <mixed-citation xml:lang="en">Mostow, G. D. Quasi-Conformal Mappings in $n$-Spaces and the Rigidity of Hyperbolic Space Forms, Publications Mathematiques de l'Institut des Hautes Scientifiques, 1968, vol. 34, pp. 53-104. DOI: 10.1007/BF02684590.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R6">
        <label>6</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Gromov, M. Groups of Polynomial Growth and Expanding Maps, Publications Mathematiques de l'Institut des Hautes Scientifiques,1981, vol. 53, pp. 53-78. DOI: 10.1007/BF02698687.</mixed-citation>
          <mixed-citation xml:lang="en">Gromov, M. Groups of Polynomial Growth and Expanding Maps, Publications Mathematiques de l'Institut des Hautes Scientifiques, 1981, vol. 53, pp. 53-78. DOI: 10.1007/BF02698687.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R7">
        <label>7</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Gromov, M. Structures Metriques Pour les Varietes Riemanniennes,United States, Boston, Birkhauser, 1999, 585 p.</mixed-citation>
          <mixed-citation xml:lang="en">Gromov, M. Structures Metriques Pour les Varietes Riemanniennes, United States, Boston, Birkhauser, 1999, 585 p.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R8">
        <label>8</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Mitchell, J. On Carnot-Caratheodory Metrics, Journal of Differential Geometry, 1981,vol. 21, no. 1, pp. 35-45. DOI: 10.4310/jdg/1214439462.</mixed-citation>
          <mixed-citation xml:lang="en">Mitchell, J. On Carnot-Caratheodory Metrics, Journal of Differential Geometry, 1981, vol. 21, no. 1, pp. 35-45. DOI: 10.4310/jdg/1214439462.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R9">
        <label>9</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Gromov, M. Carnot-Caratheodory Spaces Seen from Within, Sub-Riemannian Geometry, Progress in Mathematics, vol. 144,Basel, Birkhauser, 1981, pp. 79-323.DOI: 10.1007/978-3-0348-9210-0_2.</mixed-citation>
          <mixed-citation xml:lang="en">Gromov, M. Carnot-Caratheodory Spaces Seen from Within, Sub-Riemannian Geometry, Progress in Mathematics, vol. 144, Basel, Birkhauser, 1981, pp. 79-323.DOI: 10.1007/978-3-0348-9210-0_2.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R10">
        <label>10</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Pansu, P. Metriques de Carnot-Caratheodory et Quasiisometries des EspacesSymetriques de Rang un,  Annals of Mathematics,1989, vol. 129, pp. 1-60. DOI: 10.2307/1971484.</mixed-citation>
          <mixed-citation xml:lang="en">Pansu, P. Metriques de Carnot-Caratheodory et Quasiisometries des Espaces Symetriques de Rang un, Annals of Mathematics, 1989, vol. 129, pp. 1-60. DOI: 10.2307/1971484.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R11">
        <label>11</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Koranyi, A. and Reimann, H. M. Foundations for the Theory of Quasiconformal Mappingson the Heisenberg Group,  Advances in Mathematics, 1995, vol. 111, pp. 1-87. DOI: 10.1006/aima.1995.1017.</mixed-citation>
          <mixed-citation xml:lang="en">Koranyi, A. and Reimann, H. M. Foundations for the Theory of Quasiconformal Mappings on the Heisenberg Group, Advances in Mathematics, 1995, vol. 111, pp. 1-87. DOI: 10.1006/aima.1995.1017.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R12">
        <label>12</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Vodopyanov, S. K. Monotone Functions and Quasiconformal Mappings on CarnotGroups,  Siberian Mathematical Journal, 1996, vol. 37, no. 6,pp. 1113-1136. DOI: 10.1007/BF02106736.</mixed-citation>
          <mixed-citation xml:lang="en">Vodopyanov, S. K. Monotone Functions and Quasiconformal Mappings on Carnot Groups, Siberian Mathematical Journal, 1996, vol. 37, no. 6, pp. 1113-1136. DOI: 10.1007/BF02106736.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R13">
        <label>13</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Vodopyanov, S. K and Greshnov, A. V. On Extension of Functions of Bounded Mean Oscillation from Domains in a Space of Homogeneous Type with Intrinsic Metric, Siberian Mathematical Journal, 1995, vol. 36, no. 5, pp. 873-901.  DOI: 10.1007/BF02112531.</mixed-citation>
          <mixed-citation xml:lang="en">Vodopyanov, S. K and Greshnov, A. V. On Extension of Functions of Bounded Mean  Oscillation from Domains in a Space of Homogeneous Type with Intrinsic Metric, Siberian Mathematical Journal, 1995, vol. 36, no. 5, pp. 873-901. DOI: 10.1007/BF02112531.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R14">
        <label>14</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Vodopyanov, S. K and Greshnov, A. V. Analytical Properties of QuasiconformalMappings on Carnot Groups,  Siberian Mathematical Journal,1995, vol. 36, no. 6, pp. 1142-1151. DOI: 10.1007/BF02106836.</mixed-citation>
          <mixed-citation xml:lang="en">Vodopyanov, S. K and Greshnov, A. V. Analytical Properties of Quasiconformal Mappings on Carnot Groups, Siberian Mathematical Journal, 1995, vol. 36, no. 6, pp. 1142-1151. DOI: 10.1007/BF02106836.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R15">
        <label>15</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Vodopyanov, S. K and Greshnov, A. V. Continuation of Differentiable Functions and Quasiconformal Mappings on Carnot Groups,  Doklady Akademii Nauk, 1996, vol. 348, no. 1, pp. 15-18.</mixed-citation>
          <mixed-citation xml:lang="en">Vodopyanov, S. K and Greshnov, A. V. Continuation of Differentiable Functions and Quasiconformal Mappings on Carnot Groups, Doklady Akademii Nauk, 1996, vol. 348, no. 1, pp. 15-18.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R16">
        <label>16</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Vodopyanov, S. K and Ukhlov, A. D. Approximately Differentiable Transformations andReplacement Variables on Nilpotent Groups, Siberian Mathematical Journal, 1996, vol. 37, no. 1, pp. 70-89.DOI: 10.1007/BF02104760.</mixed-citation>
          <mixed-citation xml:lang="en">Vodopyanov, S. K and Ukhlov, A. D. Approximately Differentiable Transformations and Replacement Variables on Nilpotent Groups, Siberian Mathematical Journal, 1996, vol. 37, no. 1, pp. 70-89. DOI: 10.1007/BF02104760.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R17">
        <label>17</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Koranyi, A. and Reimann, H. M. Quasiconformal Mappings on the Heisenberg Group, Inventiones Mathematicae, 1985, vol. 80, pp. 309-338.</mixed-citation>
          <mixed-citation xml:lang="en">Koranyi, A. and Reimann, H. M. Quasiconformal Mappings on the Heisenberg Group, Inventiones Mathematicae, 1985, vol. 80, pp. 309-338.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R18">
        <label>18</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Wu, Q. Ya and Wang, W. The Beltrami Equations for Quasiconformal Mappings on StrictlyPseudoconvex Hyperplanes,   Siberian Mathematical Journal, 2012,vol. 53, no. 2, pp. 316-334. DOI: 10.1134/ S0037446612020140.</mixed-citation>
          <mixed-citation xml:lang="en">Wu, Q. Ya and Wang, W. The Beltrami Equations for Quasiconformal Mappings on Strictly Pseudoconvex Hyperplanes, Siberian Mathematical Journal, 2012, vol. 53, no. 2, pp. 316-334. DOI: 10.1134/ S0037446612020140.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R19">
        <label>19</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Isangulova, D. V. The Class of Mappings with Bounded Specific Oscillation,and Integrability of Mappings with Bounded Distortion on Carnot Groups,  Siberian Mathematical Journal, 2007, vol. 48, no. 2, pp. 249-267.DOI: 10.1007/s11202-007-0025-1.</mixed-citation>
          <mixed-citation xml:lang="en">Isangulova, D. V. The Class of Mappings with Bounded Specific Oscillation, and Integrability of Mappings with Bounded Distortion on Carnot Groups, Siberian Mathematical Journal, 2007, vol. 48, no. 2, pp. 249-267. DOI: 10.1007/s11202-007-0025-1.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R20">
        <label>20</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Bonfiglioli, A., Lanconelli, E. and Uguzzoni, F. Stratified Lie Groups and Potential Theory for Their Sub-Laplacian,Berlin-Heidelberg, Springer-Verlag, 2007.</mixed-citation>
          <mixed-citation xml:lang="en">Bonfiglioli, A., Lanconelli, E. and Uguzzoni, F. Stratified Lie Groups and Potential Theory for Their Sub-Laplacian, Berlin-Heidelberg, Springer-Verlag, 2007.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R21">
        <label>21</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Vodopyanov, S. K. Closure of Classes of Mappings with Bounded Distortion onCarnot Groups,  Siberian Advances in Mathematics, 2004, vol. 14, no. 1, pp. 84-125.</mixed-citation>
          <mixed-citation xml:lang="en">Vodopyanov, S. K. Closure of Classes of Mappings with Bounded Distortion on Carnot Groups, Siberian Advances in Mathematics, 2004, vol. 14, no. 1, pp. 84-125.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R22">
        <label>22</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Platis, I. D. Quasiconformal Mappings on the Heisenberg Group: An Overview, Handbook of Teichmuller Theory, IRMA Lectures in Mathematics and Theoretical Physics,  2016,  vol. 6,  pp. 375-393. DOI: 10.4171/161-1/12.</mixed-citation>
          <mixed-citation xml:lang="en">Platis, I. D. Quasiconformal Mappings on the Heisenberg Group: An Overview, Handbook of Teichmuller Theory, IRMA Lectures in Mathematics and Theoretical Physics,  2016, vol. 6, pp. 375-393. DOI: 10.4171/161-1/12.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R23">
        <label>23</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Bernard, A., Campbell, E. A. and Davie, A. M. Brownian Motions and Generalized Analytic and Inner Functions, Annales de l'Institut Fourier, 1979, vol. 29, no. 1, pp. 207-228.</mixed-citation>
          <mixed-citation xml:lang="en">Bernard, A., Campbell, E. A. and Davie, A. M. Brownian Motions and Generalized Analytic and Inner Functions, Annales de l'Institut Fourier, 1979, vol. 29, no. 1, pp. 207-228.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R24">
        <label>24</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Oksendal, B. Dirichlet Forms, Quasiregular Functions and Brownian Motion, Inventiones Mathematicae, 1988, vol. 91, pp. 273-297.</mixed-citation>
          <mixed-citation xml:lang="en">Oksendal, B. Dirichlet Forms, Quasiregular Functions and Brownian Motion, Inventiones Mathematicae, 1988, vol. 91, pp. 273-297.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R25">
        <label>25</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Evseev, N. A. Brownian Path Preserving Mappings on the Heisenberg Group, Journal of Mathematical Analysis and Applications,2025, vol. 548, no. 2, 129388. DOI: 10.1016/j.jmaa.2025.129388.</mixed-citation>
          <mixed-citation xml:lang="en">Evseev, N. A. Brownian Path Preserving Mappings on the Heisenberg Group, Journal of Mathematical Analysis and Applications, 2025, vol. 548, no. 2, 129388. DOI: 10.1016/j.jmaa.2025.129388.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R26">
        <label>26</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Zijian, Le. Brownian Motion, Quasiconformal Mappings and the BeltramiEquation, A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy, University of Washington, 2021.</mixed-citation>
          <mixed-citation xml:lang="en">Zijian, Le. Brownian Motion, Quasiconformal Mappings and the Beltrami Equation, A Dissertation Submitted in Partial Fulfillment of the Requirements  for the Degree of Doctor of Philosophy, University of Washington, 2021.</mixed-citation>
        </citation-alternatives>
      </ref>
      <ref id="R27">
        <label>27</label>
        <citation-alternatives>
          <mixed-citation xml:lang="ru">Calin, O. Transience of Diffusions on Heisenberg and Grushin Distributions, Journal of Geometry and Physics, 2014, vol. 77, pp. 131-142. DOI: 10.1016/j.geomphys.2013.12.010.</mixed-citation>
          <mixed-citation xml:lang="en">Calin, O. Transience of Diffusions on Heisenberg and Grushin Distributions, Journal of Geometry and Physics, 2014, vol. 77, pp. 131-142. DOI: 10.1016/j.geomphys.2013.12.010.</mixed-citation>
        </citation-alternatives>
      </ref>
    </ref-list>
  </back>
</article>
