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Haar's dyadic orthogonal system with localized convergent expansions

Contribution grade

Harmonic analysis · Exact theorem and reusable mathematical method

Reference score310,000Provisional editorial estimate of this exact contribution; its grade is assessed separately.

What changed

Haar constructs a complete orthonormal system of localized dyadic step functions on [0,1]. In its specified natural order, Fourier-Haar expansions converge uniformly for continuous functions and almost everywhere for Lebesgue-integrable functions. The proof uses localized positive averaging kernels; dense recursive partitions yield related systems.

Scientific scope

Haar constructs a complete orthonormal system of localized dyadic step functions on [0,1]. In its specified natural order, Fourier-Haar expansions converge uniformly for continuous functions and almost everywhere for Lebesgue-integrable functions. The proof uses localized positive averaging kernels; dense recursive partitions yield related systems. The basis functions are discontinuous step functions: this is not a Schauder basis made of continuous elements of C[0,1], nor a claim that arbitrary reordering preserves convergence. No general wavelet optimality, unconditionality in every space or the paper's later Sturm–Liouville results is included.

Evidence

The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The basis functions are discontinuous step functions: this is not a Schauder basis made of continuous elements of C[0,1], nor a claim that arbitrary reordering preserves convergence. No general wavelet optimality, unconditionality in every space or the paper's later Sturm–Liouville results is included.

Contributors

Provisional WRS assessment, edition 2026-10-23.3. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.

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