The EZ-transformation massless D-brane conjecture

Let $X$ be a Calabi–Yau threefold containing a subspace $E$, let $i:E\hookrightarrow X$ be the inclusion, and let $q:E\to Z$ be the map contracting $E$ to a lower-dimensional subspace $Z$. Write $\mathbf{D}(Z)$ for the bounded derived category of coherent sheaves on $Z$. EZ-transformation massless D-brane conjecture. Any D-brane that becomes massless at a point on a component of the discriminant associated with an EZ-transformation should be generated by objects of the form

$$i_*q^*\mathsf{z},\qquad \mathsf{z}\in\mathbf{D}(Z).$$

The conjecture proposes that the derived category of the contracted space $Z$ describes the massless D-branes associated with the EZ-transformation; the source gives no resolution.