I am not sure this is the right place to ask, but I give it a try anyway.
I am reading a book about how to write math. At some point the author shows the grammar rule for the possessive case: e.g. one usually writes 'Stokes's theorem', 'Bliss's book', 'van der Corput's lemma', and so on. He does not mention the so called 'Jacobi identity'. According to the general rule, I would write 'Jacobi's identity'. Is there a specific reason why we do not do it?