English
For a non-associative semiring α and a at least two, (ofNat a) ⊗ₖ B equals a blockDiagonal scaling of B with (ofNat a).
Русский
Для неассоциируемого полугруппового кольца, при a ≥ 2, (ofNat a) ⊗ₖ B равно блочно-дiагональной нормализации с a.
LaTeX
$$$ (\operatorname{ofNat}(a) : Matrix l l α) \otimes_k B = \operatorname{reindex} (\operatorname{prodComm} _) (\operatorname{prodComm} _) ( \operatorname{blockDiagonal} (\lambda _, (\operatorname{ofNat}(a) : α) \cdot B ) ) $$$
Lean4
theorem kronecker_ofNat [NonAssocSemiring α] [DecidableEq n] (A : Matrix l m α) (b : ℕ) [b.AtLeastTwo] :
A ⊗ₖ (ofNat(b) : Matrix n n α) = blockDiagonal fun _ => A <• (ofNat(b) : α) :=
kronecker_diagonal _ _