Before revision:  We also propose the non-accelerated VR based EXTRA and DIGing, and provide explicit complexities, for example, the O(( \kappa_s +n)\log\frac{1}{\epsilon}) stochastic gradient computation complexity and the O((\kappa_b+\kappa_c) \log\frac{1}{\epsilon}) communication complexity for the VR based EXTRA.
After revision:  We also propose the accelerated VR-EXTRA and VR-DIGing with both the optimal O(( \kappa_s +n)\log\frac{1}{\epsilon}) stochastic gradient computation complexity and the O((\kappa_b+\kappa_c) \log\frac{1}{\epsilon}) communication complexity for the VR based EXTRA.