Some interesting birational morphisms of smooth affine quadric $3$-folds

Cinzia Bisi, Jonathan D. Hauenstein, Tuyen Trung Truong

We study a family of birational maps of smooth affine quadric 3-folds, {over the complex numbers}, of the form $x_1{x}_4-x_2{x}_3=$ constant, which seems to have some (among many other…