The higher-dimensional fractional T1T1 conjecture

Let Tα,n\mathbf{T}^{\alpha,n} denote an elliptic vector of standard α\alpha-fractional singular integrals in Rn\mathbb{R}^{n}, and let σ\sigma and ω\omega be measures on Rn\mathbb{R}^{n}. The fractional T1T1 conjecture. The operator Tα,n\mathbf{T}^{\alpha,n} is bounded from L2(Rn;σ)L^{2}(\mathbb{R}^{n};\sigma) to L2(Rn;ω)L^{2}(\mathbb{R}^{n};\omega), namely

Tα,n(fσ)L2(Rn;ω)fL2(Rn;σ),fL2(Rn;σ),\left\|\mathbf{T}^{\alpha,n}(f\sigma)\right\|_{L^{2}(\mathbb{R}^{n};\omega)}\lesssim \left\|f\right\|_{L^{2}(\mathbb{R}^{n};\sigma)},\qquad f\in L^{2}(\mathbb{R}^{n};\sigma),

if and only if the two one-tailed A2α\mathcal{A}_{2}^{\alpha} conditions with holes, the punctured A2αA_{2}^{\alpha} conditions, and the two testing conditions hold:

Tα,n1QσL2(Rn;ω)Qσ,\left\|\mathbf{T}^{\alpha,n}\mathbf{1}_{Q}\sigma\right\|_{L^{2}(\mathbb{R}^{n};\omega)}\lesssim \sqrt{|Q|_{\sigma}}, Tα,n,dual1QωL2(Rn;σ)Qω,\left\|\mathbf{T}^{\alpha,n,\operatorname{dual}}\mathbf{1}_{Q}\omega\right\|_{L^{2}(\mathbb{R}^{n};\sigma)}\lesssim \sqrt{|Q|_{\omega}},

for all cubes QQ in Rn\mathbb{R}^{n}, whose sides need not be parallel to the coordinate axes. The conjecture seeks a complete two-weight characterization for higher-dimensional fractional singular integrals; the supplied text says that earlier results required energy conditions, but gives no resolution status for this full statement.

Sources & referencesView supporting material

Primary source

Eric T. Sawyer, Chun-Yen Shen and Ignacio Uriarte-Tuero, “The two weight T1 theorem for fractional Riesz transforms when one measure is supported on a curve”, arXiv:1505.07822 (2015).

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