English
For a unit u in the base ring, membership in the skewAdjointMatricesLieSubalgebra is invariant under scaling of J by u.
Русский
При масштабировании матрицы J единицей u принадлежность в кососопряжённых сохраняется.
LaTeX
$$$A \in skewAdjointMatricesLieSubalgebra (u \cdot J) \iff A \in skewAdjointMatricesLieSubalgebra J$$$
Lean4
theorem mem_skewAdjointMatricesLieSubalgebra_unit_smul (u : Rˣ) (J A : Matrix n n R) :
A ∈ skewAdjointMatricesLieSubalgebra (u • J) ↔ A ∈ skewAdjointMatricesLieSubalgebra J :=
by
change A ∈ skewAdjointMatricesSubmodule (u • J) ↔ A ∈ skewAdjointMatricesSubmodule J
simp only [mem_skewAdjointMatricesSubmodule, Matrix.IsSkewAdjoint, Matrix.IsAdjointPair]
constructor <;> intro h
· simpa using congr_arg (fun B => u⁻¹ • B) h
· simp [h]