On directed graphs with an independent covering set
It is shown that if a directed graph contains no odd directed cycle and, for all but finitely many nodes, either the in-degrees are finite or the out-degrees are at most one, then the directed graph contains an independent covering set. An example is given to show that a countable directed graph having no directed cycles, each of its nodes has at most out-degree two, has no independent covering set.
scientific article; zbMATH DE number 4128835