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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E25">Th18</font></span>: <a NAME="T18"><span class="comment"><font color="firebrick">:: STACKS_1:18</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">X</font> being   <a href="stacks_1.html#NM3" title="STACKS_1:NM.3">StackAlgebra</a><br/>  for <font color="Olive" title="b2">s1</font>, <font color="Olive" title="b3">s2</font> being   <a href="stacks_1.html#NM2" title="STACKS_1:NM.2">stack</a> of <font color="Olive" title="b1">X</font>  st <font color="Olive" title="b2">s1</font> <a href="stacks_1.html#R2" title="STACKS_1:pred.2">==</a> <font color="Olive" title="b3">s2</font> &amp;  not  <a href="stacks_1.html#R1" title="STACKS_1:pred.1">emp</a> <font color="Olive" title="b2">s1</font> holds <br/> <a href="stacks_1.html#K6" title="STACKS_1:func.6">top</a> <font color="Olive" title="b2">s1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="stacks_1.html#K6" title="STACKS_1:func.6">top</a> <font color="Olive" title="b3">s2</font></div></div>
