 Parseval identity for a Hilbertian basis

ID: parseval-identity-for-a-hilbertian-basis

Codex  0 Created 2026-09-24 Updated 2026-09-24

(e_{i})

⟨ x, y ⟩ = \sum_{i} ⟨ x, e_{i} ⟩ \overline{⟨ y, e_{i} ⟩}, ∥ x ∥^{2} = \sum_{i} ∣ ⟨ x, e_{i} ⟩ ∣^{2} .

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