Crepant transformation correspondence for simple Grassmannian flops

Let $X$ and $X'$ be the two varieties related by the simple Grassmannian flop under discussion, and let the isomorphism in Proposition $\mathrm{prop\_coh\_isom}$ be the cohomological isomorphism associated with the flop. Crepant transformation correspondence. The isomorphism in Proposition $\mathrm{prop\_coh\_isom}$ induces equalities between generating functions of ancestor Gromov–Witten invariants of $X$ and $X'$ after analytical continuation. This is the genus-zero crepant transformation correspondence for simple Grassmannian flops; the surrounding discussion explains that higher-genus ancestor theories can be identified via reconstruction, while the descendant correspondence requires additional care, especially concerning analytical continuation.