English
If a monoid M acts on α by uniform continuous smul, then Completion α carries a distributionally compatible M-action, i.e., it is a DistribMulAction.
Русский
Если моноид M действует на α плавно по униформной теме, то Completion α имеет совместимое действие M, то есть является DistribMulAction.
LaTeX
$$$\\mathrm{DistribMulAction}(M, \\mathrm{Completion}(\\alpha))$$$
Lean4
instance {M} [Monoid M] [DistribMulAction M α] [UniformContinuousConstSMul M α] : DistribMulAction M (Completion α) :=
{
(inferInstance :
MulAction M <|
Completion
α) with
smul_add := fun r x y ↦
induction_on₂ x y
(isClosed_eq ((continuous_fst.add continuous_snd).const_smul _)
((continuous_fst.const_smul _).add (continuous_snd.const_smul _)))
fun a b ↦ by simp only [← coe_add, ← coe_smul, smul_add]
smul_zero := fun r ↦ by rw [← coe_zero, ← coe_smul, smul_zero r] }