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Theorems · Theorem · functional analysis

Submodule.orthogonalProjectionFn_norm_sq

Deprecated since 2026-06-10Use Submodule.norm_sq_eq_add_norm_sq_starProjection instead.

∀ {𝕜 : Type u_1} {E : Type u_2} [inst : RCLike 𝕜] [inst_1 : NormedAddCommGroup E] [inst_2 : InnerProductSpace 𝕜 E]
  (K : Submodule 𝕜 E) [inst_3 : K.HasOrthogonalProjection] (v : E),
  ‖v‖ * ‖v‖ =
    ‖v - Submodule.orthogonalProjectionFn v‖ * ‖v - Submodule.orthogonalProjectionFn v‖ +
      ‖Submodule.orthogonalProjectionFn v‖ * ‖Submodule.orthogonalProjectionFn v‖
Defined in
Mathlib.Analysis.InnerProductSpace.Projection.Basic
Cited by
0 results in Mathlib
Foundations
Depth 185 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
RCLikeNormedAddCommGroupInnerProductSpaceSubmodule.HasOrthogonalProjection

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