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