English
If α has zero, each f i has zero, SMulWithZero α (f i) and NoZeroSMulDivisors α (f i) for all i, then NoZeroSMulDivisors α (∀ i, f i).
Русский
Если для каждой i множество f(i) имеет ноль и выполнено свойство NoZeroSMulDivisors α (f i) и SMulWithZero α (f i), то NoZeroSMulDivisors α (i → f i).
LaTeX
$$$$\forall i, NoZeroSMulDivisors(\alpha, f(i)) \implies NoZeroSMulDivisors(\alpha, (i \mapsto f(i))).$$$$
Lean4
instance noZeroSMulDivisors (α) [Zero α] [∀ i, Zero <| f i] [∀ i, SMulWithZero α <| f i]
[∀ i, NoZeroSMulDivisors α <| f i] : NoZeroSMulDivisors α (∀ i : I, f i) :=
⟨fun {_ _} h => or_iff_not_imp_left.mpr fun hc => funext fun i => (smul_eq_zero.mp (congr_fun h i)).resolve_left hc⟩