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<b>let </b><font color="Maroon">c<sub>1</sub></font>, <font color="Maroon">c<sub>2</sub></font> be   <a href="zf_lang.html#NM2">ZF-formula</a>;<br/>



<b>assume </b><a NAME="E1:55"/><i><font color="Green">E44</font></i>: 
<font color="Maroon">c<sub>1</sub></font> is <a href="zf_lang.html#V8" target="_self">disjunctive</a>
 ;<br/>

<b>then consider </b><font color="Maroon">c<sub>3</sub></font>, <font color="Maroon">c<sub>4</sub></font> being   <a href="zf_lang.html#NM2">ZF-formula</a><b> such that </b><br/><a NAME="E3:55"/><i><font color="Green">E45</font></i>: 
<font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>3</sub></font> <a href="zf_lang.html#K10" target="_self">'or'</a> <font color="Maroon">c<sub>4</sub></font>
 <b>by </b><i><a class="ref" href="zf_lang.html#D20" target="_self">Def20</a></i>;<br/>
<a NAME="E4:55"/>
<font color="Maroon">c<sub>1</sub></font> <a href="funct_1.html#K1">.</a> 1 <a href="hidden.html#R1">=</a> 2
 
<b>by </b><i><a class="txt" href="zf_lang.html#E3:55"><i><font color="Green">E45</font></i></a>, <a class="ref" href="zf_lang.html#T32" target="_self">Th32</a></i>;<br/>
<a NAME="E5:55"/><b>then </b>
not <font color="Maroon">c<sub>1</sub></font> is <a href="zf_lang.html#V5" target="_self">conjunctive</a>
 
<b>by </b><i><a class="ref" href="zf_lang.html#T38" target="_self">Th38</a></i>;<br/>
<b>hence </b><a NAME="E6:55"/>
( ( <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a>  <a href="zf_lang.html#K21" target="_self">the_left_argument_of</a> <font color="Maroon">c<sub>1</sub></font> implies ex <font color="Olive">b<sub>1</sub></font> being  <a href="zf_lang.html#NM2">ZF-formula</a> st <font color="Maroon">c<sub>2</sub></font> <a href="zf_lang.html#K10" target="_self">'or'</a> <font color="Olive">b<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>1</sub></font> ) &amp; ( ex <font color="Olive">b<sub>1</sub></font> being  <a href="zf_lang.html#NM2">ZF-formula</a> st <font color="Maroon">c<sub>2</sub></font> <a href="zf_lang.html#K10" target="_self">'or'</a> <font color="Olive">b<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>1</sub></font> implies <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a>  <a href="zf_lang.html#K21" target="_self">the_left_argument_of</a> <font color="Maroon">c<sub>1</sub></font> ) &amp; ( <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a>  <a href="zf_lang.html#K22" target="_self">the_right_argument_of</a> <font color="Maroon">c<sub>1</sub></font> implies ex <font color="Olive">b<sub>1</sub></font> being  <a href="zf_lang.html#NM2">ZF-formula</a> st <font color="Olive">b<sub>1</sub></font> <a href="zf_lang.html#K10" target="_self">'or'</a> <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>1</sub></font> ) &amp; ( ex <font color="Olive">b<sub>1</sub></font> being  <a href="zf_lang.html#NM2">ZF-formula</a> st <font color="Olive">b<sub>1</sub></font> <a href="zf_lang.html#K10" target="_self">'or'</a> <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>1</sub></font> implies <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a>  <a href="zf_lang.html#K22" target="_self">the_right_argument_of</a> <font color="Maroon">c<sub>1</sub></font> ) )
 <b>by </b><i><a class="txt" href="zf_lang.html#E1:55"><i><font color="Green">E44</font></i></a>, <a class="ref" href="zf_lang.html#D31" target="_self">Def31</a>, <a class="ref" href="zf_lang.html#D32" target="_self">Def32</a></i>;<br/>


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