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<b>defpred </b><font color="Maroon">S<sub>1</sub></font>[ <a href="ordinal1.html#V7" title="ORDINAL1:attr.7">natural</a>  <a href="ordinal1.html#NM1" title="ORDINAL1:NM.1">number</a> ] <b>means </b>not $1 is <a href="moebius1.html#V1" title="MOEBIUS1:attr.1">square-containing</a>;<br/>
<b>let </b><font color="Maroon" title="c1">X1</font>, <font color="Maroon" title="c2">X2</font> be   <a href="subset_1.html#NM2" title="SUBSET_1:NM.2">Subset</a> of <a href="numbers.html#K5" title="NUMBERS:func.5">NAT</a> ; <a class="txt" onclick="hs(this)" href="javascript:()"><i><font color="Red">::  thesis: </font></i></a><span class="hide"> ( ( for <font color="Olive" title="b1">n</font> being <a href="ordinal1.html#V7" title="ORDINAL1:attr.7">natural</a>  <a href="ordinal1.html#NM1" title="ORDINAL1:NM.1">number</a>  holds <br/> ( <font color="Olive" title="b1">n</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c1">X1</font> iff not <font color="Olive" title="b1">n</font> is <a href="moebius1.html#V1" title="MOEBIUS1:attr.1">square-containing</a> ) ) &amp; ( for <font color="Olive" title="b1">n</font> being <a href="ordinal1.html#V7" title="ORDINAL1:attr.7">natural</a>  <a href="ordinal1.html#NM1" title="ORDINAL1:NM.1">number</a>  holds <br/> ( <font color="Olive" title="b1">n</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">X2</font> iff not <font color="Olive" title="b1">n</font> is <a href="moebius1.html#V1" title="MOEBIUS1:attr.1">square-containing</a> ) ) implies <font color="Maroon" title="c1">X1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c2">X2</font> )</span><br/>

<b>assume </b><b>that </b><br/><a NAME="E1:33_1_2"/><i><font color="Green" title="E24">A3</font></i>: 
for <font color="Olive" title="b1">n</font> being <a href="ordinal1.html#V7" title="ORDINAL1:attr.7">natural</a>  <a href="ordinal1.html#NM1" title="ORDINAL1:NM.1">number</a>  holds <br/> ( <font color="Olive" title="b1">n</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c1">X1</font> iff not <font color="Olive" title="b1">n</font> is <a href="moebius1.html#V1" title="MOEBIUS1:attr.1">square-containing</a> )
 <b>and </b><br/><a NAME="E2:33_1_2"/><i><font color="Green" title="E25">A4</font></i>: 
for <font color="Olive" title="b1">n</font> being <a href="ordinal1.html#V7" title="ORDINAL1:attr.7">natural</a>  <a href="ordinal1.html#NM1" title="ORDINAL1:NM.1">number</a>  holds <br/> ( <font color="Olive" title="b1">n</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">X2</font> iff not <font color="Olive" title="b1">n</font> is <a href="moebius1.html#V1" title="MOEBIUS1:attr.1">square-containing</a> )
 ; <a class="txt" onclick="hs(this)" href="javascript:()"><i><font color="Red">::  thesis: </font></i></a><span class="hide"> <font color="Maroon" title="c1">X1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c2">X2</font></span><br/>

<a NAME="E3:33_1_2"/><i><font color="Green" title="E26">A5</font></i>: 
for <font color="Olive" title="b1">y</font> being   <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="numbers.html#K5" title="NUMBERS:func.5">NAT</a>  holds <br/> ( <font color="Olive" title="b1">y</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c1">X1</font> iff <font color="Maroon">S<sub>1</sub></font>[<font color="Olive" title="b1">y</font>] )
 
<b>by </b><i><a class="txt" href="moebius1.html#E1:33_1_2"><i><font color="Green" title="E24">A3</font></i></a></i>;<br/>
<a NAME="E4:33_1_2"/><i><font color="Green" title="E27">A6</font></i>: 
for <font color="Olive" title="b1">y</font> being   <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="numbers.html#K5" title="NUMBERS:func.5">NAT</a>  holds <br/> ( <font color="Olive" title="b1">y</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">X2</font> iff <font color="Maroon">S<sub>1</sub></font>[<font color="Olive" title="b1">y</font>] )
 
<b>by </b><i><a class="txt" href="moebius1.html#E2:33_1_2"><i><font color="Green" title="E25">A4</font></i></a></i>;<br/>
<b>thus </b><a NAME="E5:33_1_2"/>
<font color="Maroon" title="c1">X1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c2">X2</font>
 <b>from </b><i><a class="ref" href="subset_1.html#S2" title="SUBSET_1:sch.2">SUBSET_1:sch 2</a>(<a class="txt" href="moebius1.html#E3:33_1_2"><i><font color="Green" title="E26">A5</font></i></a>, <a class="txt" href="moebius1.html#E4:33_1_2"><i><font color="Green" title="E27">A6</font></i></a>);</i> <a class="txt" onclick="hs(this)" href="javascript:()"><i><font color="Red">::  thesis: </font></i></a><span class="hide"> verum</span><br/>


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