An application of Lazard's theory of $p$-adic Lie groups to torsion Selmer pointed sets

Abstract

We construct torsion Selmer pointed sets, which are a discrete analogue of Selmer schemes. Such torsion objects were first defined by K. Sakugawa under a hypothesis, who also established a control theorem for them. We remove the hypothesis and provide the discrete analogue in full generality, to which Sakugawa's control theorem extends as well. As a key ingredient, we use Lazard's theory to build the unipotent completion of a finitely generated group over $p$-adic integers.