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<b>let </b><font color="Maroon">L</font> be  non <a href="struct_0.html#V3">empty</a>  <a href="sheffer1.html#L1">ShefferStr</a> ;<br/>

<b>assume </b><a NAME="E1:72"/>
<font color="Maroon">L</font> is <a href="sheffer2.html#V1" target="_self">satisfying_Sh_1</a>
 ;<br/>

<a NAME="E2:72"/><b>then </b>
for <font color="Olive">x</font>, <font color="Olive">y</font>, <font color="Olive">z</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font> holds  <span class="p1">(<span class="default"><font color="Olive">x</font> <a href="sheffer1.html#K5">|</a> <span class="p2">(<span class="default"><font color="Olive">y</font> <a href="sheffer1.html#K5">|</a> <font color="Olive">z</font></span>)</span></span>)</span> <a href="sheffer1.html#K5">|</a> <span class="p1">(<span class="default"><font color="Olive">x</font> <a href="sheffer1.html#K5">|</a> <span class="p2">(<span class="default"><font color="Olive">y</font> <a href="sheffer1.html#K5">|</a> <font color="Olive">z</font></span>)</span></span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Olive">y</font> <a href="sheffer1.html#K5">|</a> <font color="Olive">y</font></span>)</span> <a href="sheffer1.html#K5">|</a> <font color="Olive">x</font></span>)</span> <a href="sheffer1.html#K5">|</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Olive">z</font> <a href="sheffer1.html#K5">|</a> <font color="Olive">z</font></span>)</span> <a href="sheffer1.html#K5">|</a> <font color="Olive">x</font></span>)</span>
 
<b>by </b><i><a class="ref" href="sheffer2.html#T51" target="_self">Th51</a></i>;<br/>
<b>hence </b><a NAME="E3:72"/>
<font color="Maroon">L</font> is <a href="sheffer1.html#V12">satisfying_Sheffer_3</a>
 <b>by </b><i><a class="ref" href="sheffer1.html#D15">SHEFFER1:def 15</a></i>;<br/>


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