English
If each G_i is a NormedCommGroup and ι is finite, then the product ∏_i G_i, with the sup-norm, is a NormedCommGroup.
Русский
Если каждый G_i — нормированная коммутативная группа, то их произведение с суп-нормой образует NormedCommGroup.
LaTeX
$$Finite product of normed commutative groups, using the sup norm.$$
Lean4
/-- Finite product of normed groups, using the sup norm. -/
@[to_additive /-- Finite product of seminormed groups, using the sup norm. -/
]
instance normedCommGroup [∀ i, NormedCommGroup (G i)] : NormedCommGroup (∀ i, G i) :=
{ Pi.seminormedGroup with
mul_comm := mul_comm
eq_of_dist_eq_zero := eq_of_dist_eq_zero }