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<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>On Some Interpolation Inequalities Due to Olga Ladyzhenskaya and Nonlinear  Partial Differential Equations</article-title>
      </title-group>
      <trans-title-group xml:lang="ru">
        <trans-title>О некоторых интерполяционных неравенствах, полученных  О. А. Ладыженской, и нелинейных уравнениях в частных производных</trans-title>
      </trans-title-group>
      <article-id pub-id-type="doi">10.46698/e0942-9744-3775-a</article-id>
      <article-id pub-id-type="publisher-id">17178</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>40</fpage>
      <lpage>49</lpage>
      <self-uri xlink:href="https://vmj.ru/eng/archive/detail.php?ELEMENT_ID=17227&amp;SECTION_ID=636">https://vmj.ru/eng/archive/detail.php?ELEMENT_ID=17227&amp;SECTION_ID=636</self-uri>
      <contrib-group>
        <contrib contrib-type="author">
          <name-alternatives>
            <name xml:lang="ru">
              <surname>Дегтярёв</surname>
              <given-names>С. П.</given-names>
            </name>
            <name xml:lang="en">
              <surname>Degtyarev</surname>
              <given-names>S. P.</given-names>
            </name>
          </name-alternatives>
          <email>spdegt@mail.ru</email>
          <xref ref-type="aff" rid="aff1"/>
        </contrib>
      </contrib-group>
      <aff-alternatives id="aff1">
        <aff xml:lang="ru">Московский технический университет связи и информатики, Россия, 111024, Москва, ул. Авиамоторная, 8a</aff>
        <aff xml:lang="en">Moscow Technical University of Communications and Informatics, 8a Aviamotornaya St., Moscow 111024, Russia</aff>
      </aff-alternatives>
      <abstract>We consider some multiplicative interpolation inequalities between the Holder space and the Lebesgue space. Multiplicative interpolation inequalities of the Gagliardo-Nirenberg type are used in the investigations of partial differential equations. Several such inequalities involving the Holder norm (seminorm) were already proved and applied. In the present paper we generalise previous results to the anisotropic "parabolic" case with another simple proof due to idea of Olga Ladyzhenskaya. The manuscript also contains an application of such Gagliardo-Nirenberg type inequality with the Holder norm. Some integral estimate and this inequality give a priori estimate of the solution to quasilinear parabolic problem in the smooth Holder classes. Moreover, using this a priori estimate, we establish the existence of solution of the quasilinear parabolic problem. In order to prove multiplicative inequality of the Gagliardo-Nirenberg type with the Holder norm we use an equivalent normalization of the higher order Holder spaces over higher order finite differences. The key technical tool is the representation of a function \(u(x,t)\) at an arbitrary fixed point \((x,t)\) over a higher order finite difference at this point and the corresponding additional sum of values at neighboring points. After that we integrate with respect to the neighboring points over the balls \(B_{r}((x,t))\) of small radius \(r\). Estimating the finite difference over the corresponding Holder seminorm, we obtain an additive inequality with the parameter \(r\), involving  the Holder and integral norms. Optimizing this inequality over \(r\) we get the multiplicative estimate of the Gagliardo-Nirenberg type with the Holder norm and the Lebesgue norm.</abstract>
      <trans-abstract xml:lang="ru">В статье рассмотрены некоторые мультипликативные интерполяционные неравенства между пространствами Гельдера и Лебега. Мультипликативные интерполяционные неравенства типа Гальярдо - Ниренберга широко используются в исследованиях по дифференциальным уравнениям вчастных производных. Ранее были доказаны и применены несколько типов таких неравенств, включающих норму (полунорму) Гельдера. Настоящая статья обобщает имеющиеся результаты на случай анизотропных "параболических" пространств, предлагая простое доказательство, основанное на идее О. А. Ладыженской. В работе приводится применение такого неравенства типа Гальярдо - Ниренберга с нормой Гельдера. Используя более слабую интегральную оценку, это неравенство позволяет легко получить априорную оценку решения квазилинейной параболической задачи в гладких классах Гельдера. На основании этой априорной оценки устанавливается существование решения этой задачи. Для доказательства мультипликативного неравенства типа Гальярдо - Ниренберга с нормой Гельдера используется эквивалентная нормировка пространств Гельдера высоких порядков в терминах поведения конечных разностей высокого порядка. Ключевой технический прием заключается в представлении значения функции \(u(x, t)\) в произвольной точке \((x, t)\) в терминах ее конечной разности высокого порядка вэтой точке, а также добавочной суммы значений функции в соседних точках. После этого производится интегрирование по соседним точкам по шарам  \(B_{r}((x, t))\) малого радиуса \(r\) с центром в \((x, t)\). Оценивая конечную разность через полунорму Гельдера, мы приходим к аддитивному неравенству с параметром\(r\), которое включает полунорму Гельдера и интегральную норму. Наконец, оптимизируя полученное аддитивное неравенство по параметру \(r\), приходим непосредственно к мультипликативному неравенству, включающему нормы Гельдера и Лебега.</trans-abstract>
      <kwd-group xml:lang="ru">
        <kwd>интерполяционные неравенства</kwd>
        <kwd>априорные оценки</kwd>
        <kwd>нелинейные дифференциальные уравнения</kwd>
      </kwd-group>
      <kwd-group xml:lang="en">
        <kwd>interpolation inequalities</kwd>
        <kwd>a priori  estimates</kwd>
        <kwd>nonlinear PDE</kwd>
      </kwd-group>
    </article-meta>
  </front>
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</article>
