Onsager's reciprocal relations generalized for magnetically ordered media eliminate symmetry restrictions for QMR in the media which have lost the center of anti-inversion as an operation of symmetry at an ordering of its magnetic subsystem. Despite the fact that some crystal groups of symmetry are devoid of the center of anti-inversion, they also don’t have QMR because of action of other operators of symmetry.
Generalized Onsager's reciprocal relations can apply to QMR in media without the center of anti-inversion as a symmetry operation for magnetic ordering. However, these conditions are met even if some crystal groups lack this center due to the influence of other symmetry operations.