Proof of proveit.linear_algebra.inner_products.simultaneous_diagonalization_as_ortho_projectors theorem

import proveit
theory = proveit.Theory() # the theorem's theory

%proving simultaneous_diagonalization_as_ortho_projectors

With these allowed/disallowed theorem/theory presumptions (e.g., to avoid circular dependencies), we begin our proof of
simultaneous_diagonalization_as_ortho_projectors:
(see dependencies)