Proof of proveit.linear_algebra.real_vec_set_is_vec_space theorem

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

%proving real_vec_set_is_vec_space

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