English
The rank of the conjugate transpose A* equals the rank of A.
Русский
Ранк сопряжённого транспонирования матрицы A равен рангу A.
LaTeX
$$$ \operatorname{rank}(A^{*}) = \operatorname{rank}(A). $$$
Lean4
/-- TODO: prove this in greater generality. -/
@[simp]
theorem rank_conjTranspose (A : Matrix m n R) : Aᴴ.rank = A.rank :=
le_antisymm
(((rank_conjTranspose_mul_self _).symm.trans_le <| rank_mul_le_left _ _).trans_eq <|
congr_arg _ <| conjTranspose_conjTranspose _)
((rank_conjTranspose_mul_self _).symm.trans_le <| rank_mul_le_left _ _)