In the boy in the striped pajamas-Why didn't shmuel know Pavel?

In "The Boy in the Striped Pajamas," Shmuel does not recognize Pavel because they belong to different worlds. Shmuel is a Jewish prisoner in the concentration camp, while Pavel is a Jewish servant working for the family of the camp commandant. Their paths rarely cross, and the oppressive environment of the camp further isolates them from one another, emphasizing the dehumanization and separation experienced by those in the camps.