English
im acts as a linear map from QuadraticAlgebra to the base ring, i.e., it is a linear functional given by the imaginary part.
Русский
im выступает как линейное отображение из QuadraticAlgebra в базовое кольцо.
LaTeX
$$$\mathrm{im}_\ell : \text{QuadraticAlgebra}(R,a,b) \to R$ is linear with toFun = im$$
Lean4
/-- `QuadraticAlgebra.im` as a `LinearMap` -/
@[simps]
def imₗ : QuadraticAlgebra R a b →ₗ[R] R where
toFun := im
map_add' _ _ := rfl
map_smul' _ _ := rfl