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<p>&nbsp;<p>
<hr noshade size="5">
<h2><a name="EltIndex"></a>
EltIndex
</h2>

Computes the index of an equation suborder of a given order

<p><p>

<h3>
Syntax:
</h3>
<pre>index := EltIndex (alpha [,Z]);</pre>

<p>

<table>
<tr>
<td>integer</td>
<td><pre>  index  </pre></td>
<td></td>
</tr>
<tr>
<td>algebraic integer</td>
<td><pre>  alpha  </pre></td>
<td></td>
</tr>
<tr>
<td>ring of integers</td>
<td><pre>  Z  </pre></td>
<td></td>
</tr>
</table>

<p>


See also:&nbsp;&nbsp;<a href="kashref.html#OrderIndexFormEquation">OrderIndexFormEquation</a>

<p>

<h3>
Description:
</h3>
Let o be an arbitrary order over Z and let \alpha be an
algebraic integer from o. The <tt> EltIndex</tt> function
returns the module index (o:Z[\alpha]). If the index
is infinite, 0 is returned.
In the relative case, Z has to be the argument that determines
the ring of the index.

<p><p>

<p>
<hr>
<p>
<h3>
Example:
</h3>
Compute the index (Z[\sqrt[4]{5}]:Z[\sqrt[4]{5}+\sqrt{5}]): 
<pre>

kash> o := Order(Z,4,5);
Generating polynomial: x^4 - 5

kash> a := Elt(o,[0,1,1,0]);
[0, 1, 1, 0]
kash> EltIndex(a);
> 21

</pre>

<p>


<hr>

<p>
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