23 Oct
2010
23 Oct
'10
5:01 p.m.
On Saturday 23 October 2010 22:53:32, Alexey Khudyakov wrote:
type family Scalar :: * -> *
class Additive v => LeftModule v where (*^) :: Scalar v -> v -> v
class Additive v => RightModule v where (^*) :: v -> Scalar v -> v
Could you give some example of data type for which (*^) ≠ flip (^*)? I couldn't imagine one.
Take any noncommutative ring R (quaternions for example) and consider the space R^n as a) a left R-module and b) a right R-module.