Documentation

Mathlib.Data.EReal.BigOperators

Big operators on extended real numbers #

This file contains elementary lemmas about finite sums in EReal.

theorem EReal.sum_mul_of_nonneg {ι : Type u_1} {s : Finset ι} {f : ι → EReal} {a : EReal} (hf : ∀ i ∈ s, 0 ≤ f i) :
(∑ i ∈ s, f i) * a = ∑ i ∈ s, f i * a
theorem EReal.mul_sum_of_nonneg {ι : Type u_1} {s : Finset ι} {f : ι → EReal} {a : EReal} (hf : ∀ i ∈ s, 0 ≤ f i) :
a * ∑ i ∈ s, f i = ∑ i ∈ s, a * f i
theorem EReal.mul_sum_of_nonneg_of_ne_top {ι : Type u_1} {s : Finset ι} {f : ι → EReal} {a : EReal} (ha : 0 ≤ a) (ha' : a ≠ ⊤) :
a * ∑ i ∈ s, f i = ∑ i ∈ s, a * f i
theorem EReal.sum_mul_of_nonneg_of_ne_top {ι : Type u_1} {s : Finset ι} {f : ι → EReal} {a : EReal} (ha : 0 ≤ a) (ha' : a ≠ ⊤) :
(∑ i ∈ s, f i) * a = ∑ i ∈ s, f i * a
@[simp]
theorem EReal.coe_finsetSum {ι : Type u_1} (s : Finset ι) (f : ι → ℝ) :
↑(∑ i ∈ s, f i) = ∑ i ∈ s, ↑(f i)