English
If each G_i is a SeminormedCommGroup and ι is finite, then the product ∏_i G_i, endowed with the sup-norm, is a SeminormedCommGroup.
Русский
Если каждый G_i — полугруппа с нормой и ι конечен, то произведение ∏_i G_i с верхней нормой является SeminormedCommGroup.
LaTeX
$$Finite product of seminormed groups, using the sup norm on the product.$$
Lean4
/-- Finite product of seminormed groups, using the sup norm. -/
@[to_additive /-- Finite product of seminormed groups, using the sup norm. -/
]
instance seminormedCommGroup [∀ i, SeminormedCommGroup (G i)] : SeminormedCommGroup (∀ i, G i) :=
{ Pi.seminormedGroup with mul_comm := mul_comm }