<img src="http://foxridge.mpiwg-berlin.mpg.de/permanent/einstein/annalen/Einst_Grund_de_1916/fulltext/img/Einst_Grund_de_191667x.png" alt=" integral c2 d w d c = 0 { c1 2 d xm d xn w = gmn---------- d c d c " class="math-display"/>
</center>
</td>
<td width="5%">(20a)</td>
</tr>
</table>
<p class="nopar"/>
<p class="noindent">ersetzen. Da </p>
<center class="par-math-display">
<img src="http://foxridge.mpiwg-berlin.mpg.de/permanent/einstein/annalen/Einst_Grund_de_1916/fulltext/img/Einst_Grund_de_191668x.png" alt=" { ( )} d w = 1- 1-@-gm-nd-xm-d-xn-d xs + g mnd-xm-d d-xn- , w 2 @ xs d c d c d c d c " class="par-math-display"/>
</center>
<p class="nopar"/>
<p class="noindent">so erhält man nach Einsetzen von
<img src="http://foxridge.mpiwg-berlin.mpg.de/permanent/einstein/annalen/Einst_Grund_de_1916/fulltext/img/Einst_Grund_de_191669x.png" alt=" ( ) d-xn- d-d-xn d d c = d c , " class="par-math-display"/>
<img src="http://foxridge.mpiwg-berlin.mpg.de/permanent/einstein/annalen/Einst_Grund_de_1916/fulltext/img/Einst_Grund_de_191670x.png" alt=" integral c2 d c xs d xs = 0 { c1 { } -d-- g-mn d xm- -1--@ g-mnd-xm-d-xn xs = d c w @ c - 2w @ x d c d c . s " class="math-display"/>
</center>
</td>
<td width="5%">(20b)</td>
</tr>
</table>
<p class="nopar"/>
<p class="noindent">Hieraus folgt wegen der freien Wählbarkeit der
<img src="http://foxridge.mpiwg-berlin.mpg.de/permanent/einstein/annalen/Einst_Grund_de_1916/fulltext/img/Einst_Grund_de_191672x.png" alt=" d2 x @ g d x d x 1 @ g d x d x gm n----m2-+ ----mn----s---m-- ------mn---m----n-= 0, d s @ xs d c d c 2 @ xs d c d c " class="par-math-display"/>
</center>
<p class="nopar"/>
<p class="noindent">oder durch bloße Änderung der Bezeichnungsweise</p>
<table width="100%" class="equation">
<tr>
<td>
<a id="x1-29r21"/>
<center class="math-display">
<img src="http://foxridge.mpiwg-berlin.mpg.de/permanent/einstein/annalen/Einst_Grund_de_1916/fulltext/img/Einst_Grund_de_191673x.png" alt=" |_ _| 2 m n g d--xa-+ s d-xmd-xn-= 0, as d s2 |_ _| d s d s " class="math-display"/>
</center>
</td>
<td width="5%">(20d)</td>
</tr>
</table>
<p class="nopar"/>
<p class="noindent">wobei nach Christoffel gesetzt ist</p>
<table width="100%" class="equation">
<tr>
<td>
<a id="x1-30r21"/>
<center class="math-display">
<img src="http://foxridge.mpiwg-berlin.mpg.de/permanent/einstein/annalen/Einst_Grund_de_1916/fulltext/img/Einst_Grund_de_191674x.png" alt=" |_ _| m n ( ) s = 1- @-gms-+ @-gns-- @ g-mn . |_ _| 2 @ xn @ xm @ xs " class="math-display"/>
</center>
</td>
<td width="5%">(21)</td>
</tr>
</table>
<p class="nopar"/>
<p class="noindent">Multipliziert man endlich (20d) mit