def __init__(self, cartan_type):
"""
TESTS::
sage: from sage.libs.coxeter3.coxeter_group import CoxeterGroup # optional - coxeter3
sage: CoxeterGroup(['A',2]) # optional - coxeter3
Coxeter group of type ['A', 2] implemented by Coxeter3
sage: TestSuite(CoxeterGroup(['A',2])).run() # optional - coxeter3
"""
Parent.__init__(self, category=(FiniteCoxeterGroups() if cartan_type.is_finite() else CoxeterGroups()))
self._coxgroup = get_CoxGroup(cartan_type)
self._cartan_type = cartan_type
def __init__(self, n=5):
r"""
INPUT:
- ``n`` - an integer with `n>=2`
Construct the n-th DihedralGroup of order 2*n
EXAMPLES::
sage: from sage.categories.examples.finite_coxeter_groups import DihedralGroup
sage: DihedralGroup(3)
The 3-th dihedral group of order 6
"""
assert n >= 2
Parent.__init__(self, category=FiniteCoxeterGroups())
self.n = n