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<b>let </b><font color="Maroon">H</font> be   <a href="zf_lang.html#NM2">ZF-formula</a>;<br/><b>let </b><font color="Maroon">x</font> be   <a href="zf_lang.html#NM1">Variable</a>;<br/><b>let </b><font color="Maroon">M</font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">v</font> be   <a href="funct_2.html#NM1">Function</a> of  <a href="zf_lang.html#K1">VAR</a> ,<font color="Maroon">M</font>; <i><font color="Red">:: according to </font></i><a class="ref" href="zf_model.html#D5">ZF_MODEL:def 5</a><br/>







<a NAME="E1:120"/>
( <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_model.html#R1">|=</a>  <a href="zf_lang.html#K8">All</a> <font color="Maroon">x</font>,<font color="Maroon">H</font> implies <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_lang1.html#K1" target="_self">/</a> <font color="Maroon">x</font>,<span class="p1">(<span class="default"><font color="Maroon">v</font> <a href="funct_2.html#K3">.</a> <font color="Maroon">x</font></span>)</span> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> )
 
<b>by </b><i/>;<br/>
<a NAME="E2:120"/><b>then </b>
( <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_model.html#R1">|=</a>  <a href="zf_lang.html#K8">All</a> <font color="Maroon">x</font>,<font color="Maroon">H</font> implies <font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_model.html#R1">|=</a> <font color="Maroon">H</font> )
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E3:120"/>
<font color="Maroon">M</font>,<font color="Maroon">v</font> <a href="zf_model.html#R1">|=</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K8">All</a> <font color="Maroon">x</font>,<font color="Maroon">H</font></span>)</span> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H</font>
 <b>by </b><i><a class="ref" href="zf_model.html#T18">ZF_MODEL:18</a></i>;<br/>


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