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<span class="kw">let </span><font color="Maroon" title="c1">H</font> be   <a href="zf_lang.html#NM2" title="ZF_LANG:NM.2">ZF-formula</a>; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide">  for <font color="Olive" title="b1">x</font>, <font color="Olive" title="b2">y</font> being   <a href="zf_lang.html#NM1" title="ZF_LANG:NM.1">Variable</a>  st <font color="Maroon" title="c1">H</font> is  <a href="zf_lang.html#V10" title="ZF_LANG:attr.10">biconditional</a>  holds <br/><font color="Maroon" title="c1">H</font> <a href="zf_lang1.html#K6" title="ZF_LANG1:func.6">/</a> (<font color="Olive" title="b1">x</font>,<font color="Olive" title="b2">y</font>) is  <a href="zf_lang.html#V10" title="ZF_LANG:attr.10">biconditional</a> </span><br/><span class="kw">let </span><font color="Maroon" title="c2">x</font>, <font color="Maroon" title="c3">y</font> be   <a href="zf_lang.html#NM1" title="ZF_LANG:NM.1">Variable</a>; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide"> ( <font color="Maroon" title="c1">H</font> is  <a href="zf_lang.html#V10" title="ZF_LANG:attr.10">biconditional</a>  implies <font color="Maroon" title="c1">H</font> <a href="zf_lang1.html#K6" title="ZF_LANG1:func.6">/</a> (<font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c3">y</font>) is  <a href="zf_lang.html#V10" title="ZF_LANG:attr.10">biconditional</a>  )</span><br/>





<span class="kw">given </span><font color="Maroon" title="c4">H1</font>, <font color="Maroon" title="c5">H2</font> being   <a href="zf_lang.html#NM2" title="ZF_LANG:NM.2">ZF-formula</a><span class="kw"> such that </span><a NAME="E2:173"/><span class="lab"><font color="Green" title="E72">A1</font></span>: 
<font color="Maroon" title="c1">H</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c4">H1</font> <a href="zf_lang.html#K12" title="ZF_LANG:func.12">&lt;=&gt;</a> <font color="Maroon" title="c5">H2</font>
 ; <span class="comment"><font color="firebrick">:: according to </font></span><a class="ref" href="zf_lang.html#D22" title="ZF_LANG:def.22">ZF_LANG:def 22</a> <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide"> <font color="Maroon" title="c1">H</font> <a href="zf_lang1.html#K6" title="ZF_LANG1:func.6">/</a> (<font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c3">y</font>) is  <a href="zf_lang.html#V10" title="ZF_LANG:attr.10">biconditional</a> </span><br/>

<a NAME="E3:173"/>
<font color="Maroon" title="c1">H</font> <a href="zf_lang1.html#K6" title="ZF_LANG1:func.6">/</a> (<font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c3">y</font>) <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">H1</font> <a href="zf_lang1.html#K6" title="ZF_LANG1:func.6">/</a> (<font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c3">y</font>)</span>)</span> <a href="zf_lang.html#K12" title="ZF_LANG:func.12">&lt;=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon" title="c5">H2</font> <a href="zf_lang1.html#K6" title="ZF_LANG1:func.6">/</a> (<font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c3">y</font>)</span>)</span>
 
<span class="kw">by</span> <span class="lab"><a class="txt" href="#E2:173"><span class="lab"><font color="Green" title="E72">A1</font></span></a>, <a class="ref" href="zf_lang1.html#T163" target="_self" title="ZF_LANG1:th.163">Th177</a></span>;<br/>
<span class="kw">hence </span><a NAME="E4:173"/>
<font color="Maroon" title="c1">H</font> <a href="zf_lang1.html#K6" title="ZF_LANG1:func.6">/</a> (<font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c3">y</font>) is  <a href="zf_lang.html#V10" title="ZF_LANG:attr.10">biconditional</a> 
 <span class="kw">by</span> <span class="lab"><a class="ref" href="zf_lang.html#T6" title="ZF_LANG:th.6">ZF_LANG:6</a></span>; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="firebrick">::  thesis: </font></span></a><span class="hide"> verum</span><br/>


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