M. Bhargava, and A. Shankar. (2010)cite arxiv:1006.1002Comment: Proofs have been considerably streamlined, and a number of clarifying details have been added; 36 pages.
H. Forssell. (2011)cite arxiv:1109.0699Comment: 32 pages. This is the first pre-print version, the final revised version can be found at http://onlinelibrary.wiley.com/doi/10.1002/malq.201100080/abstract (posting of which is not allowed by Wiley). Changes in v2: updated comments.
S. Amari, R. Karakida, and M. Oizumi. Proceedings of Machine Learning Research, volume 89 of Proceedings of Machine Learning Research, page 694--702. PMLR, (16--18 Apr 2019)
F. Nielsen. (2013)cite arxiv:1301.3578Comment: To appear in Connected at Infinity II: On the work of Indian mathematicians (R. Bhatia and C.S. Rajan, Eds.), special volume of Texts and Readings In Mathematics (TRIM), Hindustan Book Agency, 2013.