Beispiel #1
0
    def to_character(self):
        r"""
        Return the character of the representation.

        EXAMPLES:

        The trivial character::

            sage: rho = SymmetricGroupRepresentation([3])
            sage: chi = rho.to_character(); chi
            Character of Symmetric group of order 3! as a permutation group
            sage: chi.values()
            [1, 1, 1]
            sage: all(chi(g) == 1 for g in SymmetricGroup(3))
            True

        The sign character::

            sage: rho = SymmetricGroupRepresentation([1,1,1])
            sage: chi = rho.to_character(); chi
            Character of Symmetric group of order 3! as a permutation group
            sage: chi.values()
            [1, -1, 1]
            sage: all(chi(g) == g.sign() for g in SymmetricGroup(3))
            True

        The defining representation::

            sage: triv = SymmetricGroupRepresentation([4])
            sage: hook = SymmetricGroupRepresentation([3,1])
            sage: def_rep = lambda p : triv(p).block_sum(hook(p)).trace()
            sage: map(def_rep, Permutations(4))
            [4, 2, 2, 1, 1, 2, 2, 0, 1, 0, 0, 1, 1, 0, 2, 1, 0, 0, 0, 1, 1, 2, 0, 0]
            sage: [p.to_matrix().trace() for p in Permutations(4)]
            [4, 2, 2, 1, 1, 2, 2, 0, 1, 0, 0, 1, 1, 0, 2, 1, 0, 0, 0, 1, 1, 2, 0, 0]

        """
        from sage.groups.perm_gps.permgroup_named import SymmetricGroup
        Sym = SymmetricGroup(sum(self._partition))
        values = [
            self(g).trace() for g in Sym.conjugacy_classes_representatives()
        ]
        return Sym.character(values)
    def to_character(self):
        r"""
        Return the character of the representation.

        EXAMPLES:

        The trivial character::

            sage: rho = SymmetricGroupRepresentation([3])
            sage: chi = rho.to_character(); chi
            Character of Symmetric group of order 3! as a permutation group
            sage: chi.values()
            [1, 1, 1]
            sage: all(chi(g) == 1 for g in SymmetricGroup(3))
            True

        The sign character::

            sage: rho = SymmetricGroupRepresentation([1,1,1])
            sage: chi = rho.to_character(); chi
            Character of Symmetric group of order 3! as a permutation group
            sage: chi.values()
            [1, -1, 1]
            sage: all(chi(g) == g.sign() for g in SymmetricGroup(3))
            True

        The defining representation::

            sage: triv = SymmetricGroupRepresentation([4])
            sage: hook = SymmetricGroupRepresentation([3,1])
            sage: def_rep = lambda p : triv(p).block_sum(hook(p)).trace()
            sage: map(def_rep, Permutations(4))
            [4, 2, 2, 1, 1, 2, 2, 0, 1, 0, 0, 1, 1, 0, 2, 1, 0, 0, 0, 1, 1, 2, 0, 0]
            sage: [p.to_matrix().trace() for p in Permutations(4)]
            [4, 2, 2, 1, 1, 2, 2, 0, 1, 0, 0, 1, 1, 0, 2, 1, 0, 0, 0, 1, 1, 2, 0, 0]

        """
        from sage.groups.perm_gps.permgroup_named import SymmetricGroup

        Sym = SymmetricGroup(sum(self._partition))
        values = [self(g).trace() for g in Sym.conjugacy_classes_representatives()]
        return Sym.character(values)