Approximation of signals (functions) of Lip(α, p), (p > 1)-class by trigonometric polynomials

. Given a function f in the class Lip( α,p ) (0 < α 6 1 ,p > 1), Mittal and Singh (2014) approximated such an f by using trigonometric polynomials, which are the n th terms of either certain Riesz mean or Nörlund mean trans-forms of the Fourier series representation for f . They showed that the degree of approximation is O (( λ ( n )) − α ) and extended two theorems of Leindler (2005) where he had weakened the conditions on { p n } given by Chandra (2002) to more general classes of triangular matrix methods. We obtain the same degree of approximation for a more general class of lower triangular matrices.