Automorphism groups of ${\mathbb{P}}^1$-bundles over geometrically ruled surfaces

Pascal Fong

We classify the pairs $(X,\pi )$, where $\pi :X\to S$ is a ${\mathbb{P}}^1$-bundle over a non-rational geometrically ruled surface $S$ and ${\mathrm{Aut}}^{\circ }(X)$ is relatively maxim…