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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E3">Th4</font></span>: <a NAME="T4"><span class="comment"><font color="firebrick">:: ZF_COLLA:4</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">E</font> being   non  <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>   <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a> <br/>  for <font color="Olive" title="b2">A</font>, <font color="Olive" title="b3">B</font> being   <a href="ordinal1.html#NM3" title="ORDINAL1:NM.3">Ordinal</a>  st <font color="Olive" title="b2">A</font> <a href="ordinal1.html#R1" title="ORDINAL1:pred.1">c=</a> <font color="Olive" title="b3">B</font> holds <br/> <a href="zf_colla.html#K1" title="ZF_COLLA:func.1">Collapse</a> (<font color="Olive" title="b1">E</font>,<font color="Olive" title="b2">A</font>) <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a>  <a href="zf_colla.html#K1" title="ZF_COLLA:func.1">Collapse</a> (<font color="Olive" title="b1">E</font>,<font color="Olive" title="b3">B</font>)</div></div>
