2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/104869We show that the invariants of a free associative algebra of finite rank under a linear action of a finite-dimensional Hopf algebra generated by group-like and skew-primitive elements form a finitely generated algebra exactly when the action is scalar. This generalizes an analogous result for group actions by automorphisms obtained by Dicks and Formanek, and Kharchenko.Rings and Algebras16S10; 16W30text