On a theorem of Kisin

TL;DR

This paper offers a straightforward proof of Kisin's theorem concerning the restriction of crystalline Galois representations to specific subgroups, simplifying the understanding of this important result.

Contribution

It introduces a simplified proof of Kisin's theorem, making the result more accessible and easier to understand.

Findings

Proof of Kisin's theorem is simplified

Clarifies the behavior of crystalline representations under restriction

Enhances understanding of Galois representations

Abstract

The note provides a simple proof of Kisin's theorem about the restriction of crystalline representations to certain subgroup of the Galois group.