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<b>let </b><font color="Maroon" title="c1">p</font>, <font color="Maroon" title="c2">q</font> be   <a href="zf_lang.html#NM2" title="ZF_LANG:NM.2">ZF-formula</a>;<br/>



<a NAME="E1:5"/>
<font color="Maroon" title="c1">p</font> <a href="zf_lang.html#K10" title="ZF_LANG:func.10">'or'</a> <font color="Maroon" title="c2">q</font> is <a href="zf_lang.html#V8" title="ZF_LANG:attr.8">disjunctive</a>
 
<b>by </b><i><a class="ref" href="zf_lang.html#T22" title="ZF_LANG:th.22">ZF_LANG:22</a></i>;<br/>
<a NAME="E2:5"/><b>then </b>
<font color="Maroon" title="c1">p</font> <a href="zf_lang.html#K10" title="ZF_LANG:func.10">'or'</a> <font color="Maroon" title="c2">q</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K21" title="ZF_LANG:func.21">the_left_argument_of</a> <span class="p2">(<span class="default"><font color="Maroon" title="c1">p</font> <a href="zf_lang.html#K10" title="ZF_LANG:func.10">'or'</a> <font color="Maroon" title="c2">q</font></span>)</span></span>)</span> <a href="zf_lang.html#K10" title="ZF_LANG:func.10">'or'</a> <span class="p1">(<span class="default"><a href="zf_lang.html#K22" title="ZF_LANG:func.22">the_right_argument_of</a> <span class="p2">(<span class="default"><font color="Maroon" title="c1">p</font> <a href="zf_lang.html#K10" title="ZF_LANG:func.10">'or'</a> <font color="Maroon" title="c2">q</font></span>)</span></span>)</span>
 
<b>by </b><i><a class="ref" href="zf_lang.html#T59" title="ZF_LANG:th.59">ZF_LANG:59</a></i>;<br/>
<b>hence </b><a NAME="E3:5"/>
(  <a href="zf_lang.html#K21" title="ZF_LANG:func.21">the_left_argument_of</a> <span class="p1">(<span class="default"><font color="Maroon" title="c1">p</font> <a href="zf_lang.html#K10" title="ZF_LANG:func.10">'or'</a> <font color="Maroon" title="c2">q</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c1">p</font> &amp;  <a href="zf_lang.html#K22" title="ZF_LANG:func.22">the_right_argument_of</a> <span class="p1">(<span class="default"><font color="Maroon" title="c1">p</font> <a href="zf_lang.html#K10" title="ZF_LANG:func.10">'or'</a> <font color="Maroon" title="c2">q</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c2">q</font> )
 <b>by </b><i><a class="ref" href="zf_lang.html#T48" title="ZF_LANG:th.48">ZF_LANG:48</a></i>;<br/>


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