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<div><span class="kw">theorem </span><a NAME="T3"><span class="comment"><font color="firebrick">:: DBLSEQ_3:3</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">X</font>, <font color="Olive" title="b2">Y</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="b3">f</font> being   <a href="funct_2.html#NM1" title="FUNCT_2:NM.1">Function</a> of <span class="p1"><a href="zfmisc_1.html#K2" title="ZFMISC_1:func.2">[:</a><span class="default"><font color="Olive" title="b1">X</font>,<font color="Olive" title="b2">Y</font></span><a href="zfmisc_1.html#K2" title="ZFMISC_1:func.2">:]</a></span>,<a href="numbers.html#K6" title="NUMBERS:func.6">ExtREAL</a> holds   <a href="funct_4.html#K13" title="FUNCT_4:func.13">~</a> <span class="p1">(<span class="default"><a href="dblseq_3.html#K1" title="DBLSEQ_3:func.1">-</a> <font color="Olive" title="b3">f</font></span>)</span> <a href="funct_2.html#R2" title="FUNCT_2:pred.2">=</a>  <a href="dblseq_3.html#K1" title="DBLSEQ_3:func.1">-</a> <span class="p1">(<span class="default"><a href="funct_4.html#K13" title="FUNCT_4:func.13">~</a> <font color="Olive" title="b3">f</font></span>)</span></div></div>
