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Theorems · Theorem · functional analysis

real_inner_add_sub_eq_zero_iff

∀ {F : Type u_3} [inst : SeminormedAddCommGroup F] [inst_1 : InnerProductSpace ℝ F] (x y : F),
  inner ℝ (x + y) (x - y) = 0 ↔ ‖x‖ = ‖y‖

The sum and difference of two vectors are orthogonal if and only if they have the same norm.

Defined in
Mathlib.Analysis.InnerProductSpace.Basic
Cited by
2 results in Mathlib
Foundations
Depth 163 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
SeminormedAddCommGroupInnerProductSpace

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