for a Coxeter  group which is a permutation  group, using the low level functions for   permutations  is   usually  much   faster  than   manipulating  lists representing reduced expressions.</p><p>The only Coxeter group constructors implemented in this module are <code>coxsym</code> and  <code>coxgroup</code>; the last constructor takes  a Cartan matrix and builds the corresponding  Coxeter group as  a matrix group.  The module <a href="weyl.html#Chevie.Weyl"><code>Weyl</code></a> defines  other methods fo