This entry is about a section of the text
A group functor is a group object in a functor category.
A -group functor is a k-functor? which is a group functor.
A group functor which is a scheme is called -group scheme or just -group. The category of -groups is denoted by .
The terminology of group-functors is mainly used in the theory of algebraic groups in algebraic geometry. If is a group functor the multiplication morphism is called group law on .