<h3>7 <span class="Heading">Other Functions in the <strong class="pkg">PERMUT</strong> Package</span></h3>
<p>In this chapter we define some miscellaneous functions which have appeared in the context of permutability, or some functions which have been used for some of the functions of the package.</p>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ AllSubnormalSubgroups</code>( <var class="Arg">G</var> )</td><td class="tdright">( attribute )</td></tr></table></div>
<p>This function computes all subnormal subgroups of <var class="Arg">G</var>. The method used to obtain this list consists in beginning with the list of all normal subgroups of <var class="Arg">G</var> and by adding all normal subgroups of the subgroups in the list until no new subnormal subgroups appear. This computes the complete list of subgroups, not only a representative of each conjugacy class as other functions do.</p>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ PrimesDividingSize</code>( <var class="Arg">G</var> )</td><td class="tdright">( attribute )</td></tr></table></div>
<p>This attribute gives a list of primes dividing the size of the finite group <var class="Arg">G</var>, without repetitions. Its code has been borrowed from the <strong class="pkg">GAP</strong> manual.</p>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ SylowSubgroups</code>( <var class="Arg">G</var> )</td><td class="tdright">( attribute )</td></tr></table></div>
<p>This attribute returns a list composed by one Sylow subgroup for every prime dividing the size of <var class="Arg">G</var>. If <var class="Arg">G</var> is soluble, then it returns a Sylow system or Sylow basis of <var class="Arg">G</var> by means of the function <code class="func">SylowSystem</code> (<a href="../../../doc/ref/chap39_mj.html#X832E8E6B8347B13F"><span class="RefLink">Reference: SylowSystem</span></a>) (a set composed of a Sylow subgroup for each prime dividing the order of <var class="Arg">G</var> permuting in pairs).</p>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ IsSCGroup</code>( <var class="Arg">G</var> )</td><td class="tdright">( property )</td></tr></table></div>
<p>This property is <code class="keyw">true</code> if <var class="Arg">G</var> is an SC-group, and <code class="keyw">false</code> otherwise. A group <var class="Arg">G</var> is an SC-group if all its chief factors are simple. Note that a soluble group <var class="Arg">G</var> is an SC-group if and only if <var class="Arg">G</var> is supersoluble. The method used to check this property uses the chief series if its is available or the group is not soluble.</p>
<p>Since the methods for insoluble groups might on the computation of a chief series with the function <code class="func">ChiefSeries</code> (<a href="../../../doc/ref/chap39_mj.html#X7BDD116F7833800F"><span class="RefLink">Reference: ChiefSeries</span></a>), they might not be available if the group is not given as a permutation group.</p>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ IsSylowTowerGroup</code>( <var class="Arg">G</var> )</td><td class="tdright">( property )</td></tr></table></div>
<p>This property takes the value <code class="keyw">true</code> if <span class="SimpleMath">\(G\)</span> has a Sylow tower of supersoluble type, and <code class="keyw">false</code> otherwise.</p>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ Permutizer</code>( <var class="Arg">G</var>, <var class="Arg">U</var> )</td><td class="tdright">( function )</td></tr></table></div>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ Permutiser</code>( <var class="Arg">G</var>, <var class="Arg">U</var> )</td><td class="tdright">( function )</td></tr></table></div>
<p>The permutiser of a subgroup <var class="Arg">U</var> of a group <var class="Arg">G</var> is the subgroup generated by all cyclic subgroups of <var class="Arg">G</var> which permute with <var class="Arg">U</var>. If <var class="Arg">U</var> is permutable in <var class="Arg">G</var> (in particular, if <var class="Arg">U</var> is normal in <var class="Arg">G</var>), then its permutizer coincides with <varclass="Arg">G</var>.</p>
<div class="func"><table class="func" width="100%"><tr><td class="tdleft"><code class="func">‣ AllGeneratorsCyclicPGroup</code>( <var class="Arg">g</var>, <var class="Arg">p</var> )</td><td class="tdright">( function )</td></tr></table></div>
<p>This auxiliary function returns the list of all generators of the cyclic <span class="SimpleMath">\(p\)</span>-group generated by the <span class="SimpleMath">\(p\)</span>-element <span class="SimpleMath">\(g\)</span>. Here <span class="SimpleMath">\(p\)</span> is a prime number. Since this function is not intended to be used in interactive mode, no check is done that the argument is a <span class="SimpleMath">\(p\)</span>-element.</p>