Metric spaces with complexity of the smallest infinite ordinal number
  In this paper, we are concerned with the study on metric spaces with complexity of the smallest infinite ordinal number. We give equivalent formulations of the definition of metric spaces with complexity of the smallest infinite ordinal number and prove that the exact complexity of the finite product of wreath product is the smallest infinite ordinal number. Consequently, we obtain the complexity of (ZwrZ)wrZ is w+1. 
Jingming Zhu and Yan Wu
math.GR