>an introduction to differential geometry I did find "Functional Differential Geometry": https://mitp-content-server.mit.edu/books/content/sectbyfn/books_pres

>an introduction to differential geometry I did find "Functional Differential Geometry": https://mitp-content-server.mit.edu/books/content/sectbyfn/books_pres_0/9580/9580.pdf?dl=1 https://mitp-content-server.mit.edu/books/content/sectbyfn/b... ...which uses Scheme to teach differential geometry. I would need to learn quite a bit more before tackling that book. Maybe something like: "Structure and Interpretation of Classical Mechanics"? https://mitp-content-server.mit.edu/books/content/sectbyfn/books_pres_0/9579/sicm_edition_2.zip/book.html https://mitp-content-server.mit.edu/books/content/sectbyfn/b... ...but even there, it looks like I would need to start with something more basic.