English
Every BilinForm on M corresponds to a Matrix via toMatrixAux, and this correspondence is inverse to the BilinForm-to-matrix equivalence.
Русский
Каждая билинейная форма на M сопоставляется матрицей через toMatrixAux, и эта взаимосвязь обратна эквивалентности билинейной формы и матрицы.
LaTeX
$$$ \text{BilinForm.toMatrixAux} b: BilinForm \to Matrix $ (and its inverse).$$
Lean4
/-- The map from `Matrix n n R` to bilinear forms on `n → R`.
This is an auxiliary definition for the equivalence `Matrix.toBilin'`. -/
def toBilin'Aux [Fintype n] (M : Matrix n n R₁) : BilinForm R₁ (n → R₁) :=
Matrix.toLinearMap₂'Aux _ _ M