  A method of constructing covariant differential calculi on a quantum
homogeneous space is devised. The function algebra X of the quantum homogeneous
space is assumed to be a left coideal of a coquasitriangular Hopf algebra H and
to contain the coefficients of any matrix over H which is the two-sided inverse
of one with entries in X. The method is based on partial derivatives. For the
quantum sphere of Podles and the quantizations of symmetric spaces due to
Noumi, Dijkhuizen and Sugitani the construction produces the subcalculi of the
standard bicovariant calculus on the quantum group.
