</span><a class="link" href="../../container/generation/functions/vector_tie.html" title="vector_tie"><code class="computeroutput"><span class="identifier">vector_tie</span></code></a><span class="special">(</span><span class="identifier">a</span><span class="special">,</span><span class="identifier">b</span><span class="special">),</span> <span class="identifier">_1</span> <span class="special">-=</span> <span class="identifier">_2</span><span class="special">);</span>
    <span class="identifier">assert</