What is the theme in The Sandman by Neil Gaiman?

Oppression is another theme in the story. In "A Dream of a Thousand Cats," the cats are oppressed creatures. They are an underclass of society, living at the pleasure of the wealthy upper class. They may be pets, not work animals, but their lot in life is little more than slavery. The Siamese cat's owners are just that: owners. They don't like her choice of lover, so they kill her children. The idea of such a thing happening to a human being is nearly unimaginable.