The relative-position representation can always be mapped back to the absolute position z t i by: One of the biggest advantages for using such vector-based representations is that at each step, updating the relative-position representations is simply extending the relative-position matrix R t with the next predicted relative position, because the (left, middle, right) relations described in  Equation 3stay unchanged once they are created.
we update R t as follows: (5) where we use r t+1 t+1 to represent the relative position at step t + 1.