English
The norm is compatible with inner product addition: norm congruence holds under addition in the product.
Русский
Норма совместима с суммой по внутреннему произведению; сохранение нормы при суммировании элементов в произведении.
LaTeX
$$$\\mathrm{Norm}_{A}\\bigl(\\sum_i (\\langle x_i, y_i \\rangle_A)\\bigr) = \\sum_i \\langle x_i, y_i \\rangle_A$$$
Lean4
/-- A normed additive commutative group structure on `C⋆ᵐᵒᵈ(A, Π i, E i)` with the wrong topology,
uniformity and bornology. This is only used to build the instance with the correct forgetful
inheritance data. -/
noncomputable def normedAddCommGroupPiAux : NormedAddCommGroup C⋆ᵐᵒᵈ(A, Π i, E i) :=
NormedAddCommGroup.ofCore (CStarModule.normedSpaceCore A)