English
For each i with One(A_i) and DecidableEq ι, the map x ↦ Pi.mulSingle i x as a function ∀ i, A_i is continuous.
Русский
Для фиксированного i функция x ↦ Pi.mulSingle i x, рассматриваемая как элемент ∀ i, A_i, непрерывна.
LaTeX
$$$\text{Continuous}(\lambda x, (\Pi i, A_i).\, \operatorname{mulSingle}(i,x))$$$
Lean4
/-- `Pi.mulSingle i x` is continuous in `x`. -/
@[to_additive (attr := continuity) /-- `Pi.single i x` is continuous in `x`. -/
]
theorem continuous_mulSingle [∀ i, One (A i)] [DecidableEq ι] (i : ι) :
Continuous fun x => (Pi.mulSingle i x : ∀ i, A i) :=
continuous_const.update _ continuous_id