Proof of proveit.logic.booleans.conjunction.unary_and_is_true_reduction theorem

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

%proving unary_and_is_true_reduction

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