finsum_mem_pair

∀ {α : Type u_1} {M : Type u_5} [inst : AddCommMonoid M] {f : α → M} {a b : α},
  a ≠ b → ∑ᶠ (i : α) (_ : i ∈ {a, b}), f i = f a + f b

The sum of f i over i ∈ {a, b}, a ≠ b, is equal to f a + f b.

Defined in: Mathlib.Algebra.BigOperators.Finprod
Cited by: 0 results in Mathlib
Foundations: Depth 88 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes: AddCommMonoid

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