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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#L3">ShefferOrthoLattStr</a> ;<br/>

<b>assume </b><a NAME="E1:168_1_1"/>
( <font color="Maroon">L</font> is <a href="sheffer2.html#V1" target="_self">satisfying_Sh_1</a> &amp; <font color="Maroon">L</font> is <a href="sheffer1.html#V9">properly_defined</a> )
 ;<br/>

<b>then reconsider </b><font color="Maroon">L'</font> = <font color="Maroon">L</font> as  non <a href="struct_0.html#V3">empty</a> <a href="sheffer1.html#V9">properly_defined</a> <a href="sheffer2.html#V1" target="_self">satisfying_Sh_1</a>  <a href="sheffer1.html#L3">ShefferOrthoLattStr</a>  ;<br/>
<a NAME="E3:168_1_1"/>
<font color="Maroon">L'</font> is  non <a href="struct_0.html#V3">empty</a> <a href="lattices.html#V10">Lattice-like</a> <a href="lattices.html#V17">Boolean</a>  <a href="sheffer1.html#L3">ShefferOrthoLattStr</a> 
 
;<br/>
<b>hence </b><a NAME="E4:168_1_1"/>
( <font color="Maroon">L</font> is <a href="lattices.html#V17">Boolean</a> &amp; <font color="Maroon">L</font> is <a href="lattices.html#V10">Lattice-like</a> )
 ;<br/>


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