2 problems

Let $X$ be the hypersurface of a flop of length $\ell$, and let $M$ and $M^+$ be the maximal Cohen--Macaulay modules associated with the two resolutions. A matrix factorization of…

Let $X$ be the contracted threefold of a flop of length $\ell$, with resolutions $Y$ and $Y^+$, and let a maximal Cohen--Macaulay module on $X$ have rank $\ell$. The Grassmann blow…