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<b>let </b><font color="Maroon">c<sub>6</sub></font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/>

<b>assume </b><a NAME="E1:5"/><i><font color="Green">E3</font></i>: 
<font color="Maroon">c<sub>6</sub></font> is <a href="ordinal1.html#V1">epsilon-transitive</a>
 ;<br/>

<b>hence </b><a NAME="E2:5"/>
( <font color="Maroon">c<sub>6</sub></font> <a href="zf_model.html#R2">|=</a>  <a href="zf_model.html#K8">the_axiom_of_unions</a>  implies for <font color="Olive">b<sub>1</sub></font> being   <a href="hidden.html#M1">set</a>  st <font color="Olive">b<sub>1</sub></font> <a href="hidden.html#R2">in</a> <font color="Maroon">c<sub>6</sub></font> holds <br/> <a href="tarski.html#K3">union</a> <font color="Olive">b<sub>1</sub></font> <a href="hidden.html#R2">in</a> <font color="Maroon">c<sub>6</sub></font> )
 <b>by </b><i><a class="ref" href="zfmodel1.html#T4" target="_self">Th4</a></i>;<br/>

<b>assume </b><a NAME="E3:5"/>
for <font color="Olive">b<sub>1</sub></font> being   <a href="hidden.html#M1">set</a>  st <font color="Olive">b<sub>1</sub></font> <a href="hidden.html#R2">in</a> <font color="Maroon">c<sub>6</sub></font> holds <br/> <a href="tarski.html#K3">union</a> <font color="Olive">b<sub>1</sub></font> <a href="hidden.html#R2">in</a> <font color="Maroon">c<sub>6</sub></font>
 ;<br/>

<a NAME="E4:5"/><b>then </b>
for <font color="Olive">b<sub>1</sub></font> being   <a href="subset_1.html#M1">Element</a> of <font color="Maroon">c<sub>6</sub></font> holds  <a href="tarski.html#K3">union</a> <font color="Olive">b<sub>1</sub></font> <a href="hidden.html#R2">in</a> <font color="Maroon">c<sub>6</sub></font>
 
;<br/>
<b>hence </b><a NAME="E5:5"/>
<font color="Maroon">c<sub>6</sub></font> <a href="zf_model.html#R2">|=</a>  <a href="zf_model.html#K8">the_axiom_of_unions</a> 
 <b>by </b><i><a class="txt" href="zfmodel1.html#E1:5"><i><font color="Green">E3</font></i></a>, <a class="ref" href="zfmodel1.html#T4" target="_self">Th4</a></i>;<br/>


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