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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="E1:18"/>
<font color="Maroon">H</font> is <a href="zf_lang.html#V9">conditional</a>
 ;<br/>

<a NAME="E2:18"/><b>then </b>
<font color="Maroon">H</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K25">the_antecedent_of</a> <font color="Maroon">H</font></span>)</span> <a href="zf_lang.html#K11">=&gt;</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K26">the_consequent_of</a> <font color="Maroon">H</font></span>)</span>
 
<b>by </b><i><a class="ref" href="zf_lang.html#T65">ZF_LANG:65</a></i>;<br/>
<a NAME="E3:18"/><b>then </b>
<font color="Maroon">H</font> <a href="hidden.html#R1">=</a>  <a href="zf_lang.html#K6">'not'</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="zf_lang.html#K25">the_antecedent_of</a> <font color="Maroon">H</font></span>)</span> <a href="zf_lang.html#K7">'&amp;'</a> <span class="p2">(<span class="default"><a href="zf_lang.html#K6">'not'</a> <span class="p3">(<span class="default"><a href="zf_lang.html#K26">the_consequent_of</a> <font color="Maroon">H</font></span>)</span></span>)</span></span>)</span>
 
;<br/>
<a NAME="E4:18"/><b>then </b>
 <a href="zf_lang.html#K20">the_argument_of</a> <font color="Maroon">H</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K25">the_antecedent_of</a> <font color="Maroon">H</font></span>)</span> <a href="zf_lang.html#K7">'&amp;'</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K6">'not'</a> <span class="p2">(<span class="default"><a href="zf_lang.html#K26">the_consequent_of</a> <font color="Maroon">H</font></span>)</span></span>)</span>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E5:18"/>
 <a href="zf_lang.html#K25">the_antecedent_of</a> <font color="Maroon">H</font> <a href="hidden.html#R1">=</a>  <a href="zf_lang.html#K21">the_left_argument_of</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K20">the_argument_of</a> <font color="Maroon">H</font></span>)</span>
 <b>by </b><i/>;<br/>


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