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

Computes the Hasse-Witt invariant of a global function field.

<p><p>

<h3>
Syntax:
</h3>
<pre>s := AlffHasseWittInvariant(F);</pre>

<p>

<table>
<tr>
<td>integer</td>
<td><pre>  s  </pre></td>
<td></td>
</tr>
<tr>
<td>global function field</td>
<td><pre>  F  </pre></td>
<td></td>
</tr>
</table>

<p>


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

<p>

<h3>
Description:
</h3>
Let F/k be a global function field of characteristic p.
Let F \bar{k} / \bar{k} be the constant field extension
by the algebraic closure \bar{k} of k within an algebraic
closure \bar{F} of F.
Consider the subgroup Cl^0(F \bar{k} / \bar{k})[p] of
p-torsion elements of the group of divisor classes of
degree zero. This function returns its dimension as an
FF_p-vector space. Possible values range from 0 to g,
where g is the genus of F/k.

<p><p>

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

<pre>

</pre>

<p>


<hr>

<p>
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