Abstract The Schröder-Bernstein Theorem for sets is well-known. A dual of the Schröder-
Bernstein Theorem is that two sets with surjection maps onto each other are isomorphic …

The well known Schröder-Bernstein Theorem states that any two sets with one to one maps
into each other are isomorphic. The question of whether any two (subisomorphic or) direct …