html#math_toolkit.quat_mem_fun.subtraction_operators">operator -= </a><span class="special">(</span><span class="identifier">quaternion</span><span class="special">&lt;</span><span class="identifier">X</span><span class="special">&gt;</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">rhs</span><span class="special">);</span>

   <span class="identifier">quaternion</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special"