2 problems

Let $f\in\bK[x_0,\dots,x_n]$ define a smooth cubic hypersurface $X=V(f)\subset\bP^n$, and let $\cH_f$ be its Hessian hypersurface. Say that $f$ is of Thom–Sebastiani type if, after…

Let $[f]\in U$ be general, and let $Y$ be the associated surface. The surface $Y$ has two $2$-torsion line bundles: $[?]$ the line bundle $[?]$ defined by $K_Y=3H|_Y+\eta$, and…