English
The product M × N inherits a distributive mul action from its factors: (r) · (m, n) distributes over multiplication coordinatewise, and r · 1 = 1.
Русский
Произведение M × N наследует действие умножения от факторов: (r) · (m, n) распределяется по умножению по координатам, и r · 1 = 1.
LaTeX
$$$a \\cdot ((m_1, n_1)(m_2, n_2)) = (a \\cdot m_1, a \\cdot n_1)(a \\cdot m_2, a \\cdot n_2)$$$$
Lean4
instance distribMulAction {R : Type*} [Monoid R] [AddMonoid M] [AddMonoid N] [DistribMulAction R M]
[DistribMulAction R N] : DistribMulAction R (M × N) :=
{ Prod.mulAction, Prod.distribSMul with }