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Rudin's Homogeneous Basis Problem


Rudin's homogeneous basis problem asks whether the Hardy space H^2 on the unit ball of C^d, for fixed d>=2, has an orthonormal basis of homogeneous polynomials with a common uniform bound on the boundary of the ball. The polynomials must be holomorphic functions, and the inner product uses normalized surface measure on the boundary. The bound must be independent of both the polynomial's degree and its position in the basis.

Gonçalves et al. (2026) and Wang et al. (2026) gave affirmative solutions in every fixed dimension. Wang et al. (2026) obtained a basis {p_j} satisfying

 sup_(j)||p_j||_infty<=exp(d/2lnd+O(d)),

where O is big-O notation and the implicit constant is independent of d. Wang et al. (2026) report ChatGPT assistance with mathematical methods and with checking intermediate computations and estimates.


See also

Hardy Space, Homogeneous Polynomial, Orthonormal Basis

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References

Gonçalves, F.; Ferreira, J. P.; and Radziwiłł, M. "Uniformly Bounded Orthonormal Bases of Homogeneous Polynomials on the Complex Sphere." 9 Oct 2026. https://arxiv.org/abs/2610.14160.Wang, P.; Zhang, F.; and Zhu, Z. "Rudin's Problem on Uniformly Bounded Homogeneous Orthonormal Bases." 21 Oct 2026. https://arxiv.org/abs/2610.29946.

Cite this as:

Weisstein, Eric W. "Rudin's Homogeneous Basis Problem." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/RudinsHomogeneousBasisProblem.html

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