English
For NNReal finite two-element case with weights summing to 1, the rpow mean inequality holds for all p≥1.
Русский
Для двух элементов с весами, сумма которых равна 1, неравенство Холдерa верно.
LaTeX
$$$\bigl( w_1 z_1 + w_2 z_2 \bigr)^p \le w_1 z_1^p + w_2 z_2^p$$$
Lean4
/-- Weighted generalized mean inequality, version for two elements of `ℝ≥0` and real exponents. -/
theorem rpow_arith_mean_le_arith_mean2_rpow (w₁ w₂ z₁ z₂ : ℝ≥0) (hw' : w₁ + w₂ = 1) {p : ℝ} (hp : 1 ≤ p) :
(w₁ * z₁ + w₂ * z₂) ^ p ≤ w₁ * z₁ ^ p + w₂ * z₂ ^ p :=
by
have h := rpow_arith_mean_le_arith_mean_rpow univ ![w₁, w₂] ![z₁, z₂] ?_ hp
· simpa [Fin.sum_univ_succ] using h
· simp [hw', Fin.sum_univ_succ]