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  <front>
    <journal-meta>
      <journal-id>authorea</journal-id>
      <publisher>
        <publisher-name>Authorea</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.22541/au.169648215.54013495/v1</article-id>
      <title-group>
        <article-title>&lt;article class="ltx_document"&gt;
&lt;div id="p1" class="ltx_para"&gt;
documentclassarticle

 
&lt;/div&gt;
&lt;section id="S1" class="ltx_section"&gt;
&lt;h2 class="ltx_title ltx_title_section"&gt;&lt;span class="ltx_tag ltx_tag_section"&gt;1 &lt;/span&gt;Abstract&lt;/h2&gt;

&lt;div id="S1.p1" class="ltx_para"&gt;
We prove results on unique continuation at the boundary for the solutions of real analytic elliptic partial differential equations of the form
&lt;table id="S1.Ex1" class="ltx_equation ltx_eqn_table"&gt;

&lt;tbody&gt;&lt;tr class="ltx_equation ltx_eqn_row ltx_align_baseline"&gt;
&lt;td class="ltx_eqn_cell ltx_eqn_center_padleft"/&gt;
&lt;td class="ltx_eqn_cell ltx_align_center"&gt;&lt;math id="S1.Ex1.m1" class="ltx_Math" alttext="\sum_{i,j=1}^{n}a_{ij}(x)\frac{\partial^{2}u}{\partial x_{i}\partial x_{j}}+%&amp;#10;\sum_{k=1}^{n}b_{k}(x)\frac{\partial u}{\partial x_{k}}+c(x)u=0" display="block"&gt;&lt;mrow&gt;&lt;mo movablelimits="false"&gt;&amp;#x2211;&lt;/mo&gt;&lt;msub&gt;&lt;mi/&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mi/&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/msup&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;msub&gt;&lt;mi/&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo stretchy="false"&gt;(&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo stretchy="false"&gt;)&lt;/mo&gt;&lt;mfrac&gt;&lt;mrow&gt;&lt;mo rspace="0em"&gt;&amp;#x2202;&lt;/mo&gt;&lt;msup&gt;&lt;mi/&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msup&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo rspace="0em"&gt;&amp;#x2202;&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;msub&gt;&lt;mi/&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/msub&gt;&lt;mo lspace="0em" rspace="0em"&gt;&amp;#x2202;&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;msub&gt;&lt;mi/&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/mfrac&gt;&lt;mo rspace="0.055em"&gt;+&lt;/mo&gt;&lt;mo movablelimits="false"&gt;&amp;#x2211;&lt;/mo&gt;&lt;msub&gt;&lt;mi/&gt;&lt;mrow&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mi/&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/msup&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;msub&gt;&lt;mi/&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/msub&gt;&lt;mo stretchy="false"&gt;(&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo stretchy="false"&gt;)&lt;/mo&gt;&lt;mfrac&gt;&lt;mrow&gt;&lt;mo rspace="0em"&gt;&amp;#x2202;&lt;/mo&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo rspace="0em"&gt;&amp;#x2202;&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;msub&gt;&lt;mi/&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/mfrac&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mo stretchy="false"&gt;(&lt;/mo&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo stretchy="false"&gt;)&lt;/mo&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/td&gt;
&lt;td class="ltx_eqn_cell ltx_eqn_center_padright"/&gt;&lt;/tr&gt;&lt;/tbody&gt;
&lt;/table&gt;
This work is motivated by and generalized the main results of , &lt;cite class="ltx_cite ltx_citemacro_cite"&gt;[&lt;span class="ltx_ref ltx_missing_citation ltx_ref_self"&gt;berhanu2021boundary&lt;/span&gt;]&lt;/cite&gt;,&lt;cite class="ltx_cite ltx_citemacro_cite"&gt;[&lt;span class="ltx_ref ltx_missing_citation ltx_ref_self"&gt;berhanu2021local&lt;/span&gt;]&lt;/cite&gt;, X.Huang et al in
,&lt;cite class="ltx_cite ltx_citemacro_cite"&gt;[&lt;span class="ltx_ref ltx_missing_citation ltx_ref_self"&gt;huang1993unique&lt;/span&gt;]&lt;/cite&gt;,&lt;cite class="ltx_cite ltx_citemacro_cite"&gt;[&lt;span class="ltx_ref ltx_missing_citation ltx_ref_self"&gt;huang1995hopf&lt;/span&gt;]&lt;/cite&gt; and M.S Baouendi and L.P. Rothschild in
&lt;cite class="ltx_cite ltx_citemacro_cite"&gt;[&lt;span class="ltx_ref ltx_missing_citation ltx_ref_self"&gt;baouendi1993local&lt;/span&gt;]&lt;/cite&gt;
Key words: Elliptic partial differential equation ; Hopf Lemma ; Unique continuation principle ; Real analytic hypersurface ; Real analytic functions
&lt;/div&gt;
&lt;/section&gt;
&lt;section id="bib" class="ltx_bibliography"&gt;
&lt;h2 class="ltx_title ltx_title_bibliography"&gt;References&lt;/h2&gt;

&lt;ul id="bib.L1" class="ltx_biblist"&gt;
&lt;/ul&gt;
&lt;/section&gt;</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author" corresp="no">
          <contrib-id contrib-id-type="orcid">0009-0009-4947-0218</contrib-id>
          <name>
            <surname>Li</surname>
            <given-names>Chengzhi</given-names>
          </name>
        </contrib>
      </contrib-group>
      <pub-date date-type="preprint" publication-format="electronic">
        <day>5</day>
        <month>10</month>
        <year>2023</year>
      </pub-date>
      <self-uri xlink:href="https://doi.org/10.22541/au.169648215.54013495/v1">This preprint is available at https://doi.org/10.22541/au.169648215.54013495/v1</self-uri>
      <abstract abstract-type="abstract">
        <article class="ltx_document">
<div id="p1" class="ltx_para">
<p>documentclassarticle

 </p>
</div>
<section id="S1" class="ltx_section">
<h2 class="ltx_title ltx_title_section"><span class="ltx_tag ltx_tag_section">1 </span>Abstract</h2>

<div id="S1.p1" class="ltx_para">
<p>We prove results on unique continuation at the boundary for the solutions of real analytic elliptic partial differential equations of the form</p>
<table id="S1.Ex1" class="ltx_equation ltx_eqn_table">

<tbody><tr class="ltx_equation ltx_eqn_row ltx_align_baseline">
<td class="ltx_eqn_cell ltx_eqn_center_padleft"/>
<td class="ltx_eqn_cell ltx_align_center"><math id="S1.Ex1.m1" class="ltx_Math" alttext="\sum_{i,j=1}^{n}a_{ij}(x)\frac{\partial^{2}u}{\partial x_{i}\partial x_{j}}+%&#10;\sum_{k=1}^{n}b_{k}(x)\frac{\partial u}{\partial x_{k}}+c(x)u=0" display="block"><mrow><mo movablelimits="false">∑</mo><msub><mi/><mrow><mi>i</mi><mo>,</mo><mi>j</mi><mo>=</mo><mn>1</mn></mrow></msub><msup><mi/><mi>n</mi></msup><mi>a</mi><msub><mi/><mrow><mi>i</mi><mi>j</mi></mrow></msub><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo><mfrac><mrow><mo rspace="0em">∂</mo><msup><mi/><mn>2</mn></msup><mi>u</mi></mrow><mrow><mo rspace="0em">∂</mo><mi>x</mi><msub><mi/><mi>i</mi></msub><mo lspace="0em" rspace="0em">∂</mo><mi>x</mi><msub><mi/><mi>j</mi></msub></mrow></mfrac><mo rspace="0.055em">+</mo><mo movablelimits="false">∑</mo><msub><mi/><mrow><mi>k</mi><mo>=</mo><mn>1</mn></mrow></msub><msup><mi/><mi>n</mi></msup><mi>b</mi><msub><mi/><mi>k</mi></msub><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo><mfrac><mrow><mo rspace="0em">∂</mo><mi>u</mi></mrow><mrow><mo rspace="0em">∂</mo><mi>x</mi><msub><mi/><mi>k</mi></msub></mrow></mfrac><mo>+</mo><mi>c</mi><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo><mi>u</mi><mo>=</mo><mn>0</mn></mrow></math></td>
<td class="ltx_eqn_cell ltx_eqn_center_padright"/></tr></tbody>
</table>
<p>This work is motivated by and generalized the main results of , <cite class="ltx_cite ltx_citemacro_cite">[<span class="ltx_ref ltx_missing_citation ltx_ref_self">berhanu2021boundary</span>]</cite>,<cite class="ltx_cite ltx_citemacro_cite">[<span class="ltx_ref ltx_missing_citation ltx_ref_self">berhanu2021local</span>]</cite>, X.Huang et al in
,<cite class="ltx_cite ltx_citemacro_cite">[<span class="ltx_ref ltx_missing_citation ltx_ref_self">huang1993unique</span>]</cite>,<cite class="ltx_cite ltx_citemacro_cite">[<span class="ltx_ref ltx_missing_citation ltx_ref_self">huang1995hopf</span>]</cite> and M.S Baouendi and L.P. Rothschild in
<cite class="ltx_cite ltx_citemacro_cite">[<span class="ltx_ref ltx_missing_citation ltx_ref_self">baouendi1993local</span>]</cite>
Key words: Elliptic partial differential equation ; Hopf Lemma ; Unique continuation principle ; Real analytic hypersurface ; Real analytic functions</p>
</div>
</section>
<section id="bib" class="ltx_bibliography">
<h2 class="ltx_title ltx_title_bibliography">References</h2>

<ul id="bib.L1" class="ltx_biblist">
</ul>
</section></article>
      </abstract>
      <kwd-group kwd-group-type="author-created">
        <kwd>ca</kwd>
        <kwd>electrostatic discharge</kwd>
        <kwd>low noise amplifiers</kwd>
        <kwd>noise</kwd>
        <kwd>wideband amplifiers</kwd>
      </kwd-group>
    </article-meta>
  </front>
</article>
