In this paper, we have established a theorem concerning the degree of approximation of functions f Lip by means of the product summability method (E. 1) (N. p. q) applied to the Fourier series associated with a function. The result offers new insights into the convergence behavior and approximation properties of such summation techniques within the Lipschitz class, highlighting the effectiveness of product summability in Fourier analysis.
Jens et al. (2025) studied this question.