<div class="dem">    
On va montrer l'existence et l'unicit de \( r \) et \( s \).
<ul style="list-style:none;">
</description_item></li><li>
\fold{mainS2S2F_description_item1}{<span class="enum_item">Existence:</span>

}

</li><li>
\fold{mainS2S2F_description_item2}{<span class="enum_item">Unicit:</span>

}

</li></ul>

 

</div> <div class="fin"> Fin de la dmonstration</div>