arXiv subjects

Nina Morishige

Publications and source records attributed to Nina Morishige.

2 recordsLinked to original sources

arXiv2021

Genus zero Gopakumar-Vafa invariants of the Banana manifold

The Banana manifold $X_{\text{Ban}}$ is a compact Calabi-Yau threefold constructed as the conifold resolution of the fiber product of a generic rational elliptic surface with itself, first studied by Bryan. We compute Katz's genus 0 Gopakumar-Vafa invariants of fiber curve classes on the Banana manifold $X_{\text{Ban}}\to \mathbf{P}^1$. The weak Jacobi form of weight -2 and index 1 is the associated generating function for these genus 0 Gopakumar-Vafa invariants. The invariants are shown to be an actual count of structure sheaves of certain possibly nonreduced genus 0 curves on the universal cover of the singular fibers of $X_{\text{Ban}}\to \mathbf{P}^1$.

math.AG↗

arXiv2021

Genus zero Gopakumar-Vafa invariants of Multi-Banana configurations

The multi-Banana configuration $\widehat{F}_{mb}$ is a local Calabi-Yau threefold of Schoen type. Namely, $\widehat{F}_{mb}$ is a conifold resolution of $\widehat{I}_v \times_{\bf{D}} \widehat{I}_w$, where $\widehat{I}_v \to {\bf{D}}$ is an elliptic surface over a formal disc ${\bf{D}}$ with an $I_v$ singulararity on the central fiber. We generalize the technique developed in our earlier paper to compute genus 0 Gopakumar-Vafa invariants of certain fiber curve classes. We illustrate the computation explicitly for $v=1$ and $v=w=2$. The resulting partition function can be expressed in terms of elliptic genera of $\bf{C}^2$, or classical theta functions, respectively.

math.AG↗