4. Bohman correlation function The Bohman correlation function is given by R(xi x j|) = d k=1 R(xik x jk |) where

4. Bohman correlation function The Bohman correlation function is given by R(xi − x j|ξ) =  d k=1 R(xik − x jk |ξ) where R(xik − x jk |ξ) is given by  1 − xik−x jk θk cos  π(xik−x jk ) θk  + 1 π sin  π(xik−x jk ) θk  if |xik − x jk | < θk 0 if θk ≤ |xik − x jk | , and ξ represents the parameters (θ1, θ2 ..., θd ), and θk > 0. Repeat Exercise 1 with the Bohman correlation function and d = 1.