I thought this was interesting, in the 9 January 2003 Nature Magazine "50 years ago" column: * * * * Gregario Ricci-Curbastro, inventor of the tensor calculus, was born at Lugo, in Italy, on January 12, 1853. The absolute differential calculus, as he himself called it, gained little attention until Einstein used it for the formulation of general relativity, even though it had reached a mature form by 1895, after some ten years of growth. It was so little thought of, indeed, that in 1901 Ricci was denied the Italian Royal Prize in mathematics on the ground that the calculus was "useful but not essential for the treatment of some mathematical questions." Nevertheless he himself retained a belief in its value... In 1912 Einstein's attention was directed to it by his colleague, Marcel Grossman, and the outcome was the relativistic theory of gravitation published in 1916...The relativistic principle of covariance, namely, that the general laws of physics can be expressed in a form which is independent of the co-ordinate system, has a meaning only in so far as there exists a way of expressing them in such a form. The Ricci calculus provides a means of doing so...The tensor calculus is fully established as one of the main instruments of modern mathematics, and gives its inventor a permanent place in the history of the subject. [From Nature, 10 January 1953] Thane Plambeck 650 321 4884 office 650 323 4928 fax http://www.qxmail.com/home.htm