Any vedic sentence which expresses the identity of the individual and the supreme deserves to be called a mahavaki. Four are taken by convention and tradition as four mahavakis, one each one representing each of the vedas. So we'e going to do an investigation of the atman. By the way, this vergis a very cute story about this approach. I may be told you sometime, but i'll repeat it here. Ganasa and cartika are the sons of shiva and pavety. The daughters are lakmi and sarsati, lasmithe goddess of wealth,. And ganesha and kartik are the two boys.