Proof of proveit.logic.sets.enumeration.true_for_all_then_true_for_each theorem

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

%proving true_for_all_then_true_for_each

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