English
If α is nonempty and M acts faithfully on β, then the induced action of M on α×β is faithful in the right coordinate.
Русский
Если α непусто и M действует верно на β, то на α×β действует верно по правой координате.
LaTeX
$$$[Nonempty α] \\ [FaithfulSMul M β] \\Rightarrow FaithfulSMul M (α × β)$$$
Lean4
@[to_additive]
instance faithfulSMulRight [Nonempty α] [FaithfulSMul M β] : FaithfulSMul M (α × β) where
eq_of_smul_eq_smul
h :=
let ⟨a⟩ := ‹Nonempty α›
eq_of_smul_eq_smul fun b : β => by injection h (a, b)