  We introduce a general framework for associating to a homogeneous quantum
principal bundle a Yetter-Drinfeld module structure on the cotangent space of
the base calculus. The holomorphic and anti-holomorphic Heckenberger-Kolb
calculi of the quantum Grassmannians are then presented in this framework. This
allows us to express the calculi in terms of the corresponding Nichols
algebras. The extension of this result to all irreducible quantum flag
manifolds is then conjectured.
