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

Return a bound for the prime divisors to be considered
for the approximation of the class number of a global
function field.

<p><p>

<h3>
Syntax:
</h3>
<pre>b := AlffClassNumberApproxBound(q, g, a);
b := AlffClassNumberApproxBound(F, a);</pre>

<p>

<table>
<tr>
<td>integer</td>
<td><pre>  b  </pre></td>
<td>approximation bound</td>
</tr>
<tr>
<td>integers</td>
<td><pre>  q, g  </pre></td>
<td>exact constant field size and genus</td>
</tr>
<tr>
<td>alff</td>
<td><pre>  F  </pre></td>
<td>global function field</td>
</tr>
<tr>
<td>real</td>
<td><pre>  a  </pre></td>
<td>\in R^{> 1}</td>
</tr>
</table>

<p>


See also:&nbsp;&nbsp;<a href="kashref.html#AlffClassNumberApprox">AlffClassNumberApprox</a>, <a href="kashref.html#AlffClassGroup">AlffClassGroup</a>, <a href="kashref.html#AlffLPoly">AlffLPoly</a>, <a href="kashref.html#AlffInit">AlffInit</a>, <a href="kashref.html#AlffOrders">AlffOrders</a>

<p>

<h3>
Description:
</h3>
Let F/k be a global function field of genus g over the exact
constant field of q elements. This function computes b \in Z
such that frac{2g}{q^{1/2}-1} cdot frac{q^{-b/2}}{b+1}
\;<\; \log(a) / 2 holds.
See function <tt> AlffClassNumberApprox()</tt>.

<p><p>

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

<pre>

</pre>

<p>


<hr>

<p>
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