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<b>let </b><font color="Maroon">G1</font> be   <a href="zf_lang.html#NM2">ZF-formula</a>;<br/><b>let </b><font color="Maroon">G2</font> be   <a href="zf_lang.html#NM2">ZF-formula</a>;<br/><b>let </b><font color="Maroon">H1</font> be   <a href="zf_lang.html#NM2">ZF-formula</a>;<br/><b>let </b><font color="Maroon">H2</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">y</font> be   <a href="zf_lang.html#NM1">Variable</a>;<br/>











<a NAME="E1:163"/>
( ( <font color="Maroon">G1</font> <a href="zf_lang.html#K12">&lt;=&gt;</a> <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H1</font> <a href="zf_lang.html#K12">&lt;=&gt;</a> <font color="Maroon">H2</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> implies ( <font color="Maroon">G1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H2</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">G2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H1</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> ) ) &amp; ( <font color="Maroon">G1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H2</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">G2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H1</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> implies <font color="Maroon">G1</font> <a href="zf_lang.html#K12">&lt;=&gt;</a> <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H1</font> <a href="zf_lang.html#K12">&lt;=&gt;</a> <font color="Maroon">H2</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> ) &amp; ( <font color="Maroon">G1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H2</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> implies ( <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H1</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H2</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> ) ) &amp; ( <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H1</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H2</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> implies <font color="Maroon">G1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H1</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H2</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> ) &amp; ( <font color="Maroon">G2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H1</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> implies ( <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H1</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H2</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> ) ) &amp; ( <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H1</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H2</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> implies <font color="Maroon">G2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H2</font> <a href="zf_lang.html#K11">=&gt;</a> <font color="Maroon">H1</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> ) )
 
<b>by </b><i><a class="ref" href="zf_lang1.html#T72" target="_self">Th72</a>, </i>;<br/>
<b>hence </b><a NAME="E2:163"/>
( <font color="Maroon">G1</font> <a href="zf_lang.html#K12">&lt;=&gt;</a> <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">H1</font> <a href="zf_lang.html#K12">&lt;=&gt;</a> <font color="Maroon">H2</font></span>)</span> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> iff ( <font color="Maroon">G1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H1</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">G2</font> <a href="hidden.html#R1">=</a> <font color="Maroon">H2</font> <a href="zf_lang1.html#K6" target="_self">/</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> ) )
 ;<br/>


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