Let H∞ be a W∗
closed subalgebra of L∞(m) with identity. We generalize here some classical
properties of the couple of linear vector spaces (L1(m),L∞(m)) to the couple
(L1(m)∕H∞⊥,H∞). We obtain, for instance, a characterization of weakly
relatively compact subsets of L1(m)∕H∞⊥ analogous to the Dunford-Pettis
theorem. To this end, we assume a legitimate hypothesis on the peak sets of
H∞.