Quantum cluster characters of Hall algebras revisited

Let Q be a finite acyclic valued quiver. We define bialgebra structure and an integration map on the Hall algebra associated to morphism category of projective representations Q. As application, we recover surjective homomorphism defined in [12], which realizes principal coefficient quantum cluster $$\mathcal {A}\,_q(Q)$$ as sub-quotient morphisms. Moreover, also Caldero–Chapoton formula, well some multiplication formulas between characters.