English
For any matrix M, and any b: n → α with a preorder α, M.charmatrix.BlockTriangular b is equivalent to M.BlockTriangular b.
Русский
Для любой матрицы M и отображения b: n → α с частичным порядком α, charmatrix(M)_BLOCKTriangular b эквивалентна M.BlockTriangular b.
LaTeX
$$$M.\\text{charmatrix.BlockTriangular } b \;\\leftrightarrow\\; M.\\text{BlockTriangular } b$$$
Lean4
@[simp]
theorem charmatrix_blockTriangular_iff {α : Type*} [Preorder α] {M : Matrix n n R} {b : n → α} :
M.charmatrix.BlockTriangular b ↔ M.BlockTriangular b :=
by
rw [charmatrix, scalar_apply, RingHom.mapMatrix_apply, (blockTriangular_diagonal _).sub_iff_right]
simp [BlockTriangular]