ON BIALGEBRAS AND HOPF ALGEBRAS OF ORIENTED GRAPHS
ON BIALGEBRAS AND HOPF ALGEBRAS OF ORIENTED GRAPHS
We define two coproducts for cycle-free oriented graphs, thus building up two commutative connected graded Hopf algebras, such that one is a comodule-coalgebra on the other, thus generalizing the result obtained in [2] for Hopf algebras of rooted trees.