2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/65349Let $k$ be a commutative ring, $H$ a faithfully flat Hopf algebra with bijective antipode, $A$ a $k$-flat right $H$-comodule algebra. We investigate when a relative Hopf module is projective over the subring of coinvariants $B=A^{{\rm co}H}$, and we study the semisimplicity of the category of relative Hopf modules.15 pagesQuantum AlgebraRings and Algebras16W30text