Some saturation classes for deferred Riesz and deferred Nörlund means

One of main problem in approximation theory is determination a saturation class for given method. The problem of determining a saturation class has been considered by Zamanski, Sunouchi and Watari and others. Mohaparta and Russel have considered some direct and inverse theorems in approximation of functions. Sunouchi and Watari have studied the Riesz means of type \(n\). In [5], Goel et al. have extended these results by considering Nörlund means. In this paper, we examine some direct and inverse theorems in approximation of functions under weaker conditions by considering Deferred Riesz means and Deferred Nörlund means. Also, we extent above mentioned results.