English
There is a formal multilinear series qExpansionFormalMultilinearSeries n f which encodes the q-expansion coefficients via a canonical multilinear map.
Русский
Существует формальная многочестная линейная серия qExpansionFormalMultilinearSeries, кодирующая коэффициенты q-разложения через канонические многочлены.
LaTeX
$$$qExpansionFormalMultilinearSeries\; n\; f : \text{FormalMultilinearSeries } \mathbb{C} \mathbb{C} \mathbb{C}$$$
Lean4
/-- The `q`-expansion of a level `n` modular form, bundled as a `FormalMultilinearSeries`.
TODO: Maybe get rid of this and instead define a general API for converting `PowerSeries` to
`FormalMultilinearSeries`.
-/
def qExpansionFormalMultilinearSeries : FormalMultilinearSeries ℂ ℂ ℂ := fun m ↦
(qExpansion n f).coeff m • ContinuousMultilinearMap.mkPiAlgebraFin ℂ m _