English
The symmetric/decomposed inverse respects multiplication: (decompose 𝒜).symm (x y) = (decompose 𝒜).symm x · (decompose 𝒜).symm y.
Русский
Обратное разложения по симметрии сохраняет умножение: (decompose 𝒜).symm (xy) = (decompose 𝒜).symm x · (decompose 𝒜).symm y.
LaTeX
$$$ (\mathrm{decompose} 𝒜)^{-1} (xy) = (\mathrm{decompose} 𝒜)^{-1} x \cdot (\mathrm{decompose} 𝒜)^{-1} y. $$$
Lean4
@[simp]
theorem decompose_symm_mul (x y : ⨁ i, 𝒜 i) :
(decompose 𝒜).symm (x * y) = (decompose 𝒜).symm x * (decompose 𝒜).symm y :=
map_mul (decomposeRingEquiv 𝒜).symm x y