The Fourier-decay conjecture for non-degenerate analytic images of self-similar measures

Let k,dk,d be positive integers. Let μ\mu be a self-similar measure on Rk\mathbb{R}^k which is not supported in any proper affine hyperplane. Let URkU\subset\mathbb{R}^k be an open neighbourhood of supp(μ)\operatorname{supp}(\mu), and let f ⁣:URdf\colon U\to\mathbb{R}^d be real-analytic. The map ff is non-degenerate when the graph of ff is not contained in any proper affine hyperplane of Rk+d\mathbb{R}^{k+d}.

Fourier-decay conjecture. There exists σ>0\sigma>0 such that

μf^(ξ)ξσ.|\widehat{\mu_f}(\boldsymbol{\xi})|\ll |\boldsymbol{\xi}|^{-\sigma}.

The conjecture would answer the preceding questions by removing the stronger hypotheses used for the quantitative theorem, including the condition κ2>1\kappa_2>1 and holomorphicity. It predicts polynomial Fourier decay for all such non-degenerate real-analytic pushforwards.

Sources & referencesView supporting material

Primary source

Amlan Banaji and Han Yu, “Fourier transform of nonlinear images of self-similar measures: quantitative aspects”, arXiv:2503.07508 (2026).

Additional references

2 papers in this index state this conjecture (2024–2025). The statement above is taken from the most recent of them; the others are arXiv:2404.12279.

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