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<div><span class="kw">theorem </span><a NAME="T17"><span class="comment"><font color="firebrick">:: GROUP_23:17</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">I</font> being   non  <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>   <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a> <br/>  for <font color="Olive" title="b2">F</font>, <font color="Olive" title="b3">S</font> being   <a href="group_19.html#NM1" title="GROUP_19:NM.1">Group-Family</a> of <font color="Olive" title="b1">I</font> holds <br/> ( <font color="Olive" title="b3">S</font> is   <a href="group_23.html#NM2" title="GROUP_23:NM.2">Subgroup-Family</a> of <font color="Olive" title="b2">F</font> iff  for <font color="Olive" title="b4">i</font> being    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <font color="Olive" title="b1">I</font> holds  <font color="Olive" title="b3">S</font> <a href="group_7.html#K1" title="GROUP_7:func.1">.</a> <font color="Olive" title="b4">i</font> is    <a href="group_2.html#M1" title="GROUP_2:mode.1">Subgroup</a> of <font color="Olive" title="b2">F</font> <a href="group_7.html#K1" title="GROUP_7:func.1">.</a> <font color="Olive" title="b4">i</font> )</div></div>
