UpSa: upadeshasAhasrI NaiSi: naishhkarmya-siddhi, NaiSi 2.1-s would refer to the sambadhokti to verse 2.1 Ma: mAnasollAsa
During a recent phone conversation with Vidyasankar, the topic of interpretation of the mahAvAkya-s via the anvaya-vyatireka and other methods came up. Specifically, the issue was whether sha.nkara has used bhAga tyAga laxaNA in the prasthAnatrayI bhAshhya-s or the upadeshasAhasrI. I had a vague recollection that he has used it in the UpSa, and promised to dig up the verse. I had originally planned to send a private e-mail. Since it might be of some interest to at least a few list embers, I have tried to make a coherent article on this topic instead.
The most lucid explanations of the problems in the exegesis of mahAvAkya-s is found in the third chapter of the Ma and the second and third chapters of the NaiSi, both composed by sureshvarAchArya. A brief introduction to the topic is presented, closely following these two works. But I also assume a basic knowledge of sha.nkaras works. This is not an exhaustive treatment on the exegesis of the mahAvAkyas by any means. But, I hope that it'll at least give enough references for serious students of the advaita tattva. Hopefully it will also bring out a discussion of similar/varying treatment of the same subject from the prasthAnatrayI bhAshhyas and other prakaraNa grantha-s of sha.nkarAchArya, from the vArttikas of sureshvarAchArya, works of vidyAraNya mahAmuni like pa.ncadashI, etc. This is a topic which has not been discussed much on our list, and is definitely worthy of discussion. I would certainly be very enthusiastic in participating in such a discussion and hope to sharpen my learning from other list members.