abstract:In mathematics, the formal derivative is an operation on elements of a polynomial ring or a ring of formal power series that mimics the form of the derivative from calculus. Though they appear similar, the algebraic advantage of a formal derivative is that it does not rely on the notion of a limit, which is in general impossible to define for a ring.
By reducing the MREITproblem to a nonlinearoperatorequation, the formalderivativeof the operator and the formula of solution for linearization problem are given.