The complex structure of a point in the plane is defined
by the linear map
(1)
|
and corresponds to a counterclockwise rotation by . This map satisfies
(2)
| |||
(3)
| |||
(4)
|
where
is the identity map.
More generally, if
is a two-dimensional vector space, a linear map
such that
is called a complex structure on
. If
, this collapses to the previous definition.