A note on the trigonometric approximation of Lip(ω(t), p)-class

Recently, some results on the trigonometric approximation of Lip(ω(t), p)-class have been given by Srivastava and Singh (2014). In this note, we point out that one of the assumption conditions in their theorems is invalid in some cases. Thus, all conclusions in the paper based on the condition lose the foundation. Moreover, we obtain the similar results for a class of more extensive functions after deleting the mentioned condition, and weakening another condition in their theorems.