In this note, we generalize the linear duality between vector subbundles (or equivalently quotient bundles) of dual vector bundles to coherent quotients $V twoheadrightarrow mathscr{L}$ considered in arXiv:1811.12525, in the framework of Kuznetsovs homological projective duality (HPD). As an application, we obtain a generalized version of the fundamental theorem of HPD for the $mathbb{P}(mathscr{L})$-sections and the respective dual sections of a given HPD pair.