(self, gr)
return True
Test if G=self is a normal subgroup of gr.

        G is normal in gr if
        for each g2 in G, g1 in gr, g = g1*g2*g1**-1 belongs to G
        It is sufficient to check this for each g1 in gr.generator and
        g2 g2 in G.generator

        Examples
        ========

        >>> from sympy.combinatorics import Permutation
        >>> Permutation.print_cyclic = True
        >>> from sympy.combinatorics.perm_groups import PermutationGroup
        >>> a = Permutation([1, 2, 0])
        >>> b = Permutation([1, 0, 2])
        >>> G = PermutationGroup([a, b])
        >>> G1 = PermutationGroup([a, Permutation([2, 0, 1])])
        >>> G1.is_normal(G)
        True
Test if G=self is a normal subgroup of gr.
Test if G = self is a normal subgroup of gr .
def is_normal(self, gr):
        """Test if G=self is a normal subgroup of gr.

        G is normal in gr if
        for each g2 in G, g1 in gr, g = g1*g2*g1**-1 belongs to G
        It is sufficient to check this for each g1 in gr.generator and
        g2 g2 in G.generator

        Examples
        ========

        >>> from sympy.combinatorics import Permutation
        >>> Permutation.print_cyclic = True
        >>> from sympy.combinatorics.perm_groups import PermutationGroup
        >>> a = Permutation([1, 2, 0])
        >>> b = Permutation([1, 0, 2])
        >>> G = PermutationGroup([a, b])
        >>> G1 = PermutationGroup([a, Permutation([2, 0, 1])])
        >>> G1.is_normal(G)
        True

        """
        gens2 = [p._array_form for p in self.generators]
        gens1 = [p._array_form for p in gr.generators]
        for g1 in gens1:
            for g2 in gens2:
                p = _af_rmuln(g1, g2, _af_invert(g1))
                if not self.coset_factor(p, True):
                    return False
        return True
def is_normal ( self , gr ) : gens2 = [ p . _array_form for p in self . generators ] gens1 = [ p . _array_form for p in gr . generators ] for g1 in gens1 : for g2 in gens2 : p = _af_rmuln ( g1 , g2 , _af_invert ( g1 ) ) if not self . coset_factor ( p , True ) : return False return True