English
The space of square-integrable functions from α to E forms an inner product space over 𝕜 with inner product given by the integral of pointwise inner products.
Русский
Пространство квадратно интегрируемых функций образует пространство с внутренним произведением над 𝕜, где ⟪f,g⟫ = ∫ ⟪f(a), g(a)⟫ dμ.
LaTeX
$$$\\langle f,g \\rangle_{L^2} = \\int_{α} ⟪f(a), g(a)\\rangle \\, dμ(a)$$$
Lean4
instance innerProductSpace : InnerProductSpace 𝕜 (α →₂[μ] E)
where
norm_sq_eq_re_inner := norm_sq_eq_re_inner
conj_inner_symm _ _ := by simp_rw [inner_def, ← integral_conj, inner_conj_symm]
add_left := add_left'
smul_left := smul_left'