I think I touched on that in the last question in the sense that Sympathetic Joy opens to the good qualities and happiness and joy of people, learning how to have sympathy and also joy with them. Compassion opens to the suffering of people and Lovingkindness is the wishing for peace for people or beings. But they are interrelated as I said before and they both need to be practiced, not necessarily in the same meditation, but developed within ourselves in a balanced way.