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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E20">Th31</font></span>: <a NAME="T31"><span class="comment"><font color="firebrick">:: ZF_LANG:31</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">F</font>, <font color="Olive" title="b2">F1</font>, <font color="Olive" title="b3">G</font>, <font color="Olive" title="b4">G1</font> being   <a href="zf_lang.html#NM2" title="ZF_LANG:NM.2">ZF-formula</a>  st <font color="Olive" title="b1">F</font> <a href="zf_lang.html#K9" title="ZF_LANG:func.9">'or'</a> <font color="Olive" title="b3">G</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Olive" title="b2">F1</font> <a href="zf_lang.html#K9" title="ZF_LANG:func.9">'or'</a> <font color="Olive" title="b4">G1</font> holds <br/>( <font color="Olive" title="b1">F</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Olive" title="b2">F1</font> &amp; <font color="Olive" title="b3">G</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Olive" title="b4">G1</font> )</div></div>
