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

Computes B^*(a) for a global function field element a.

<p><p>

<h3>
Syntax:
</h3>
<pre>q := AlffEltBstar(a);</pre>

<p>

<table>
<tr>
<td>rational</td>
<td><pre>  q  </pre></td>
<td></td>
</tr>
<tr>
<td>global function field element</td>
<td><pre>  a  </pre></td>
<td></td>
</tr>
</table>

<p>


<h3>
Description:
</h3>
Let v_i denote the s distinct normalized valuations at the
s places of F over the infinite place of k(T), with
ramification indices e_i.
Let e = lcm { e_1, \dots, e_s } and define
 B^*:F\longrightarrow {a/e |  a\inZ}cup{-\infty} :
\alpha\longmapsto -\min_{i=1}^s v_i(\alpha)/e_i.
This function computes B^* for elements of a global
function field F. See Scho1 for further information.

<p><p>

<p>
<hr>
<p>
<h3>
Example:
</h3>

<pre>

kash> AlffInit(FF(5,2));
"Defining global variables: k, w, kT, kTf, kTy, T, y, AlffGlobals"
kash> AlffOrders(y^3+T^4+1);
"Defining global variables: F, o, oi, one"
kash> a := AlffElt(o, [0, 1, 1]);
[ 0, 1, 1 ]
kash> AlffEltBstar(a);
> 8/3

</pre>

<p>


<hr>

<p>
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