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@@ -1,7 +1,7 @@
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-<!-- 2022-02-08 Tue 06:55 -->
+<!-- 2022-02-08 Tue 17:21 -->
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<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Pre-Quantum Electrodynamics</title>
@@ -251,8 +251,8 @@ Table of contents
<ul>
<li>
-<details>
-<summary>
+<details open="">
+<summary class="toc-open">
<a href="./in.html#in">Introduction</a><span class="headline-id">in</span>
@@ -264,13 +264,17 @@ Table of contents
</li>
<li>
-<details>
-<summary>
+<details open="">
+<summary class="toc-open">
<a href="./in_t.html#in_t">Tips for the reader</a><span class="headline-id">in.t</span>
</summary>
<ul>
+<li class="toc-currentpage">
+<a href="./in_t_l.html#in_t_l">Section and equation labelling</a><span class="headline-id">in.t.l</span>
+
+</li>
<li>
<a href="./in_t_c.html#in_t_c">Contextual colors</a><span class="headline-id">in.t.c</span>
@@ -711,8 +715,8 @@ Table of contents
</li>
<li>
-<details open="">
-<summary class="toc-open">
+<details>
+<summary>
<a href="./emsm.html#emsm">Electromagnetostatics in matter</a><span class="headline-id">emsm</span>
@@ -724,8 +728,8 @@ Table of contents
</li>
<li>
-<details open="">
-<summary class="toc-open">
+<details>
+<summary>
<a href="./emsm_esm.html#emsm_esm">Electrostatics in matter</a><span class="headline-id">emsm.esm</span>
@@ -735,8 +739,8 @@ Table of contents
<a href="./emsm_esm_p.html#emsm_esm_p">Polarization</a><span class="headline-id">emsm.esm.p</span>
</li>
-<li class="toc-currentpage">
-<a href="./emsm_esm_d.html#emsm_esm_d">Dielectrics</a><span class="headline-id">emsm.esm.d</span>
+<li>
+<a href="./emsm_esm_di.html#emsm_esm_di">Dielectrics</a><span class="headline-id">emsm.esm.di</span>
</li>
<li>
@@ -1612,53 +1616,60 @@ Table of contents
</ul>
</details>
</nav>
-<ul class="navigation-links"><li>Prev: <a href="emsm_esm_p.html">Polarization <small>[emsm.esm.p]</small></a></li><li>Next: <a href="emsm_esm_fpo.html">The Field of a Polarized Object <small>[emsm.esm.fpo]</small></a></li><li>Up: <a href="emsm_esm.html">Electrostatics in matter <small>[emsm.esm]</small></a></li></ul><div id="outline-container-emsm_esm_d" class="outline-4">
-<h4 id="emsm_esm_d">Dielectrics<a class="headline-permalink" href="./emsm_esm_d.html#emsm_esm_d"><svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-link" viewBox="0 0 16 16">
+<ul class="navigation-links"><li>Prev: <a href="in_t.html">Tips for the reader <small>[in.t]</small></a></li><li>Next: <a href="in_t_c.html">Contextual colors <small>[in.t.c]</small></a></li><li>Up: <a href="in_t.html">Tips for the reader <small>[in.t]</small></a></li></ul><div id="outline-container-in_t_l" class="outline-4">
+<h4 id="in_t_l">Section and equation labelling<a class="headline-permalink" href="./in_t_l.html#in_t_l"><svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-link" viewBox="0 0 16 16">
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<path d="M9 5.5a3 3 0 0 0-2.83 4h1.098A2 2 0 0 1 9 6.5h3a2 2 0 1 1 0 4h-1.535a4.02 4.02 0 0 1-.82 1H12a3 3 0 1 0 0-6H9z"/>
-</svg></a><span class="headline-id">emsm.esm.d</span></h4>
-<div class="outline-text-4" id="text-emsm_esm_d">
+</svg></a><span class="headline-id">in.t.l</span></h4>
+<div class="outline-text-4" id="text-in_t_l">
<p>
-Let's quickly pause to give a classification of the types of responses that might be expected from
-materials.
-\subsubsection*{Permanent polarization:} here, \({\bf P} \neq 0\) even if \({\bf E} = 0\).
-These are the {\bf electrets}.
+For labelling sections and equations, I've preferred to use a semantic
+format instead of traditional numbers.
</p>
<p>
-\subsubsection*{Nonlinear dielectrics:}
-\[
-P_i = \sum_j \alpha_{ij} E_j + \sum_{jk} \beta_{ijkl} E_j E_k E_l + ...
-\]
-(even-order terms usually absent, but could be there in principle).
-\subsubsection*{Linear dielectrics:} only linear term is there. Most general:
-\[
-P_i = \varepsilon_0 \chi_{ij} E_j
-\label{Gr(4.38)}
-\]
-where \({\bf \chi}\) is the {\bf electric susceptibility tensor} (it's a tensor of rank 2),
-which cannot depend on \({\bf E}\) (otherwise we go back to the nonlinear case).
-Common in crystals, leading to for example double refraction.
-\subsubsection*{Linear isotropic dielectrics:} at a given point, the electrical properties of
-the dielectric are independent of the direction of \({\bf E}\) (isotropy). Liquids fall into
-this category. We here have
-</p>
-<div class="main div" id="org4bcb7c7">
-<p>
-\[
- {\bf P} = \varepsilon_0 \chi_e {\bf E}
- \]
+This has a number of advantages: the labelling is
</p>
+<ul class="org-ul">
+<li>easier to remember in the long run</li>
+<li>stable under tree structure modifications</li>
+</ul>
+
+
+<p>
+but also come with some things which need getting used to:
+</p>
+
+<ul class="org-ul">
+<li>the loss of clear notion of ordering</li>
+<li>abbreviations being as short as possible, thus needing learning</li>
+</ul>
+
+
+<p>
+<b>Section labelling</b>: floated right next to the title of any section, you will see the
+label together with a permalink (pointing to the main site's version
+of that particular section). Under a section's headline, you will also
+sometimes see references (in small gray letters) to corresponding sections
+in complemetary <a href="./a_l.html#a_l">literature</a>.
+</p>
+
+<p>
+<b>Equation labelling</b>: similarly to sections, some (but not all)
+equations also carry a semantic label, given in parentheses to the right
+of the equation. As per sections, a permalink is also given, together
+with corresponding equation numbers in complementary literature.
+</p>
</div>
</div>
-</div>
+
<hr><div id="postamble" class="status">
<p class="author">Author: Jean-Sébastien Caux</p>
-<p class="date">Created: 2022-02-08 Tue 06:55</p>
+<p class="date">Created: 2022-02-08 Tue 17:21</p>
<p class="validation"><a href="https://validator.w3.org/check?uri=referer">Validate</a></p>
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