Others treat PCI and similar systems as a third category, the expansion bus.

Initially they were considered spirotrichs, then treated as a separate category, before receiving their modern placement.

But, no, nobody wants to be treated as a separate category or subset.

A missing value may be treated as a yet another category.

Initially Morgan's work was accepted as integral to American history, but later it was treated as a separate category of anthropology.

Depending on the country or jurisdiction, vice crimes may or may not be treated as a separate category in the criminal codes.

A partially ordered set can be treated as a category, using the order relation as the morphisms.

Water drums are also sometimes treated as a distinct category of membranophone.

Justice Scalia, for instance, suggested during the hearing that the court might treat state motor vehicle records as a "special category" requiring special solicitude.