I am going to compute some intersection numbers on certain RZ spaces and therefore need to fully understand the deformation of $p$-divisible groups. This can be understood as deformation of displays, where displays are generalized notions of Dieudonné modules. The question is about the paper Tho...

I like the following geometric argument. Lemma. For any convex compact set $K\subset \mathbb{R}^2$ with non-empty interior there exists a point $x$ on the boundary such that the support line in $x$ is unique. Proof. Let $p$ be interior point, and $x$ the closest to $p$ point of the boundary. Sinc...