Given a compact metric space
Z with Hausdorff dimension n, if X is a metric space such that there exists a
distance-nonincreasing onto map f : Z → X, then the Hausdorff n-volumes satisfy
vol(X) ≤vol(Z). The relatively maximum volume conjecture says that if X and Z are
both Alexandrov spaces and vol(X) =vol(Z), X is isometric to a gluing space
produced from Z along its boundary ∂Z and f is length-preserving. We partially
verify this conjecture and give a further classification for compact Alexandrov
n-spaces with relatively maximum volume in terms of a fixed radius and space of
directions. We also give an elementary proof for a pointed version of the
Bishop–Gromov relative volume comparison with rigidity in Alexandrov
geometry.