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<b>let </b><font color="Maroon">H</font> be   <a href="zf_lang.html#NM2">ZF-formula</a>;<br/>

<b>assume </b><a NAME="E1:106"/>
<font color="Maroon">H</font> is <a href="zf_lang.html#V4" target="_self">negative</a>
 ;<br/>

<a NAME="E2:106"/><b>then </b>
<font color="Maroon">H</font> <a href="hidden.html#R1">=</a>  <a href="zf_lang.html#K6" target="_self">'not'</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K20" target="_self">the_argument_of</a> <font color="Maroon">H</font></span>)</span>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E3:106"/>
 <a href="zf_lang.html#K29" target="_self">Subformulae</a> <font color="Maroon">H</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K29" target="_self">Subformulae</a> <span class="p2">(<span class="default"><a href="zf_lang.html#K20" target="_self">the_argument_of</a> <font color="Maroon">H</font></span>)</span></span>)</span> <a href="xboole_0.html#K2">\/</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><font color="Maroon">H</font></span><a href="tarski.html#K1">}</a></span>
 <b>by </b><i><a class="ref" href="zf_lang.html#T38" target="_self">Th38</a></i>;<br/>


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