English
Operator dite acts componentwise: dite P A B i j = dite P (A · i j) (B · i j).
Русский
Оператор dite действует по элементам: dite P A B i j = dite P (A · i j) (B · i j).
LaTeX
$$$ \forall P\; [Decidable P], \ A : P \to Matrix m n \alpha, \ B : \neg P \to Matrix m n \alpha, \ i : m, \ j : n,\ dite P A B i j = dite P (A \cdot i j) (B \cdot i j)$$$
Lean4
protected theorem dite_apply (P : Prop) [Decidable P] (A : P → Matrix m n α) (B : ¬P → Matrix m n α) (i : m) (j : n) :
dite P A B i j = dite P (A · i j) (B · i j) := by rw [dite_apply, dite_apply]