Proof of proveit.numbers.number_sets.rational_numbers.nonpos_int_within_rational_nonpos theorem

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

%proving nonpos_int_within_rational_nonpos

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