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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E24">Th19</font></span>: <a NAME="T19"><span class="comment"><font color="firebrick">:: ARMSTRNG:19</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">X</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>  holds <br/> (  <a href="armstrng.html#K4" title="ARMSTRNG:func.4">Dependencies</a> <font color="Olive" title="b1">X</font> is  <a href="armstrng.html#V3" title="ARMSTRNG:attr.3">(F1)</a>  &amp;  <a href="armstrng.html#K4" title="ARMSTRNG:func.4">Dependencies</a> <font color="Olive" title="b1">X</font> is  <a href="armstrng.html#NV4" title="ARMSTRNG:NV.4">(F2)</a>  &amp;  <a href="armstrng.html#K4" title="ARMSTRNG:func.4">Dependencies</a> <font color="Olive" title="b1">X</font> is  <a href="armstrng.html#V4" title="ARMSTRNG:attr.4">(F3)</a>  &amp;  <a href="armstrng.html#K4" title="ARMSTRNG:func.4">Dependencies</a> <font color="Olive" title="b1">X</font> is  <a href="armstrng.html#V5" title="ARMSTRNG:attr.5">(F4)</a>  )</div></div>
