"General relativity is formulated completely in the language of tensors.
Einstein had learned about them, with great difficulty, from the geometer
Marcel Grossmann. Levi-Civita then initiated a correspondence with Einstein
to correct mistakes Einstein had made in his use of tensor analysis."
Einstein had learned about tensors "WITH GREAT DIFFICULTY."
And Levi-Civita wanted to correct Einstein's misunderstanding.
Hm... interesting... :)
