An Inverse Approximation and Saturation Order for Kantorovich Exponential Sampling Series

Abstract

In the present article, an inverse approximation result and saturation order for the Kantorovich exponential sampling series $I_{w}^{\chi}$ are established. First we obtain a relation between the generalized exponential sampling series $S_{w}^{\chi}$ and $I_{w}^{\chi}$ for the space of all uniformly continuous and bounded functions on $\mathbb{R}^{+}.$ Next, a Voronovskaya type theorem for the sampling series $S_{w}^{\chi}$ is proved. The saturation order for the series $I_{w}^{\chi}$ is obtained using the Voronovskaya type theorem. Further, an inverse result for $I_{w}^{\chi}$ is established for the class of log-H\"{o}lderian functions. Moreover, some examples of kernels satisfying the conditions, which are assumed in the hypotheses of the theorems, are discussed