We prove that under semi-local assumptions, the inexact
Newton method with a
fixed relative residual error tolerance converges -linearly to a zero of the nonlinear operator under consideration. Using this result we show that the Newton
method for minimizing a self-concordant function or to find a zero of an analytic function can be implemented with a fixed relative residual error tolerance.
In the absence of errors, our analysis retrieve the classical Kantorovich Theorem on the Newton method.