Teen Robbed

a 16-year-old was arrested for robbing a 15-year-old upper west side boy on the southwest corner of amsterdam avenue and west 86th street. police said that on oct. 13 at 4 p.m., the arrested teen held the victim while a friend snatched a gold chain from his neck and punched him in the face. cops said the other teen got away. the arrested boy was charged with robbery.