Hasse derivative

The Hasse derivative is a mathematical concept used primarily in the context of p-adic analysis and algebraic geometry, particularly within the study of p-adic fields and formal power series. It is named after the mathematician Helmut Hasse. In simple terms, the Hasse derivative can be thought of as a form of differentiation that is adapted to p-adic contexts, similar to how we differentiate functions in classical calculus.