Proper Affine Isometric Actions For Countable Discreate Group

In this article it is proved,that every countable discrete group has a proper affine isometric action on the reflexive and strictly convex Banach space:（?） and the cocycle rate of this action is not lower than the cocycle rate of 1/n^1.5.Concretely,for any countable group G,let E=（?）l²ⁿ（G）,let π be the left regular representation on E.Then there is a proper affine G-action on E such that g·v=π（g）v+b（g）,for any v（?）E,g（?）G,‖bⁿ（g）‖_2n=O(1/n^1.5),For any g（?）G,where b（g）=（bⁿ（g））_n（?）N.