In this paper, an invariant determined by a function used to guarantee the convergence of all members with l ≤ k in the family of deformed Halley iterative methods for solving nonlinear equation in complex field is given. Results include some known ones as this special cases. We get not only the error estimates of the iterative sequences {z_(n,l)} but also those of f(z_(n,l)) for all l ≤ k.

In this paper, an invariant determined by a function used to guarantee the convergence of all members with l ≤ k in the family of deformed Halley iterative methods for solving nonlinear equation in complex field is given. Results include some known ones as this special cases. We get not only the error estimates of the iterative sequences {z_(n,l)} but also those of f(z_(n,l)) for all l ≤ k.