Constant functor
Functor
context
${\bf C},{\bf D}$ … category
context
$D:\mathrm{Ob}_{\bf D}$
definiendum
$\Delta_D:{\bf C}\longrightarrow{\bf D}$
definition
$\Delta_DC:=D$
definition
$\Delta_D(f):=\mathrm{id}_D$
Discussion
Reference
Wikipedia:
Diagonal functor
nLab:
constant functor
Parents
Element of
Functor