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We interact with the world with our hands and see it through our own (egocentric) perspective. A holistic 3D understanding of such interactions from egocentric views is important for tasks … We interact with the world with our hands and see it through our own (egocentric) perspective. A holistic 3D understanding of such interactions from egocentric views is important for tasks in robotics, AR/VR, action recognition and motion generation. Accurately reconstructing such interactions in 3D is challenging due to heavy occlusion, viewpoint bias, camera distortion, and motion blur from the head movement. To this end, we designed the HANDS23 challenge based on the AssemblyHands and ARCTIC datasets with carefully designed training and testing splits. Based on the results of the top submitted methods and more recent baselines on the leaderboards, we perform a thorough analysis on 3D hand(-object) reconstruction tasks. Our analysis demonstrates the effectiveness of addressing distortion specific to egocentric cameras, adopting high-capacity transformers to learn complex hand-object interactions, and fusing predictions from different views. Our study further reveals challenging scenarios intractable with state-of-the-art methods, such as fast hand motion, object reconstruction from narrow egocentric views, and close contact between two hands and objects. Our efforts will enrich the community's knowledge foundation and facilitate future hand studies on egocentric hand-object interactions.
In this paper, we obtain the <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L Superscript p"> <mml:semantics> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:annotation encoding="application/x-tex">L^p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> restriction estimates for the truncated conic … In this paper, we obtain the <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L Superscript p"> <mml:semantics> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:annotation encoding="application/x-tex">L^p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> restriction estimates for the truncated conic surface <disp-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Sigma equals StartSet left-parenthesis xi prime comma xi Subscript n Baseline comma minus xi Subscript n Superscript negative 1 Baseline mathematical left-angle xi prime comma upper N xi Superscript prime Baseline mathematical right-angle right-parenthesis colon left-parenthesis xi prime comma xi Subscript n Baseline right-parenthesis element-of upper B Superscript n minus 1 Baseline left-parenthesis 0 comma 1 right-parenthesis times left-bracket 1 comma 2 right-bracket EndSet"> <mml:semantics> <mml:mrow> <mml:mi mathvariant="normal">Σ<!-- Σ --></mml:mi> <mml:mo>=</mml:mo> <mml:mstyle scriptlevel="0"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo maxsize="1.2em" minsize="1.2em">{</mml:mo> </mml:mrow> </mml:mstyle> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mi>n</mml:mi> </mml:msub> <mml:mo>,</mml:mo> <mml:mo>−<!-- − --></mml:mo> <mml:msubsup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mi>n</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−<!-- − --></mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo fence="false" stretchy="false">⟨<!-- ⟨ --></mml:mo> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:mi>N</mml:mi> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo fence="false" stretchy="false">⟩<!-- ⟩ --></mml:mo> <mml:mo stretchy="false">)</mml:mo> <mml:mo>:</mml:mo> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mi>n</mml:mi> </mml:msub> <mml:mo stretchy="false">)</mml:mo> <mml:mo>∈<!-- ∈ --></mml:mo> <mml:msup> <mml:mi>B</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>n</mml:mi> <mml:mo>−<!-- − --></mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy="false">)</mml:mo> <mml:mo>×<!-- × --></mml:mo> <mml:mo stretchy="false">[</mml:mo> <mml:mn>1</mml:mn> <mml:mo>,</mml:mo> <mml:mn>2</mml:mn> <mml:mo stretchy="false">]</mml:mo> <mml:mstyle scriptlevel="0"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo maxsize="1.2em" minsize="1.2em">}</mml:mo> </mml:mrow> </mml:mstyle> </mml:mrow> <mml:annotation encoding="application/x-tex">\begin{equation*} \Sigma =\big \{(\xi ’,\xi _n,-\xi _n^{-1}\langle \xi ’,N\xi ’\rangle ): (\xi ’,\xi _n)\in B^{n-1}(0,1)\times [1,2]\big \} \end{equation*}</mml:annotation> </mml:semantics> </mml:math> </disp-formula> with <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper N equals upper I Subscript n minus 1 minus m Baseline circled-plus left-parenthesis minus upper I Subscript m Baseline right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mi>N</mml:mi> <mml:mo>=</mml:mo> <mml:msub> <mml:mi>I</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>n</mml:mi> <mml:mo>−<!-- − --></mml:mo> <mml:mn>1</mml:mn> <mml:mo>−<!-- − --></mml:mo> <mml:mi>m</mml:mi> </mml:mrow> </mml:msub> <mml:mo>⊕<!-- ⊕ --></mml:mo> <mml:mo stretchy="false">(</mml:mo> <mml:mo>−<!-- − --></mml:mo> <mml:msub> <mml:mi>I</mml:mi> <mml:mi>m</mml:mi> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">N=I_{n-1-m}\oplus (-I_m)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> for <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="m less-than-or-equal-to left floor StartFraction n minus 3 Over 2 EndFraction right floor"> <mml:semantics> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>≤<!-- ≤ --></mml:mo> <mml:mo fence="false" stretchy="false">⌊<!-- ⌊ --></mml:mo> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mfrac> <mml:mrow> <mml:mi>n</mml:mi> <mml:mo>−<!-- − --></mml:mo> <mml:mn>3</mml:mn> </mml:mrow> <mml:mn>2</mml:mn> </mml:mfrac> </mml:mstyle> <mml:mo fence="false" stretchy="false">⌋<!-- ⌋ --></mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">m\leq \lfloor \tfrac {n-3}2\rfloor</mml:annotation> </mml:semantics> </mml:math> </inline-formula> provided <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="p greater-than StartFraction 2 left-parenthesis n plus 3 right-parenthesis Over n plus 1 EndFraction"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mfrac> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mi>n</mml:mi> <mml:mo>+</mml:mo> <mml:mn>3</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>n</mml:mi> <mml:mo>+</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:mfrac> </mml:mstyle> </mml:mrow> <mml:annotation encoding="application/x-tex">p&gt;\tfrac {2(n+3)}{n+1}</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. The main ingredients of the proof are the bilinear estimates of strongly separated property and a geometric distribution about caps.
In this paper, we show that Fourier restriction theorem implies the maximal and variational Fourier restriction in Lorentz space frame. The key ingredient is that we work out the induction … In this paper, we show that Fourier restriction theorem implies the maximal and variational Fourier restriction in Lorentz space frame. The key ingredient is that we work out the induction argument in Lorentz space, based on some good properties of Lorentz space. This extends Kovač's result [J. Funct. Anal., 2019, 277(10): 3355–3372] to Lorentz space frame.
In this paper, we show that Fourier restriction theorem implies the maximal and variational Fourier restriction in Lorentz space frame. The key ingredient is that we work out the induction … In this paper, we show that Fourier restriction theorem implies the maximal and variational Fourier restriction in Lorentz space frame. The key ingredient is that we work out the induction argument in Lorentz space, based on some good properties of Lorentz space. This extends Kovač's result [J. Funct. Anal., 2019, 277(10): 3355–3372] to Lorentz space frame.
We interact with the world with our hands and see it through our own (egocentric) perspective. A holistic 3D understanding of such interactions from egocentric views is important for tasks … We interact with the world with our hands and see it through our own (egocentric) perspective. A holistic 3D understanding of such interactions from egocentric views is important for tasks in robotics, AR/VR, action recognition and motion generation. Accurately reconstructing such interactions in 3D is challenging due to heavy occlusion, viewpoint bias, camera distortion, and motion blur from the head movement. To this end, we designed the HANDS23 challenge based on the AssemblyHands and ARCTIC datasets with carefully designed training and testing splits. Based on the results of the top submitted methods and more recent baselines on the leaderboards, we perform a thorough analysis on 3D hand(-object) reconstruction tasks. Our analysis demonstrates the effectiveness of addressing distortion specific to egocentric cameras, adopting high-capacity transformers to learn complex hand-object interactions, and fusing predictions from different views. Our study further reveals challenging scenarios intractable with state-of-the-art methods, such as fast hand motion, object reconstruction from narrow egocentric views, and close contact between two hands and objects. Our efforts will enrich the community's knowledge foundation and facilitate future hand studies on egocentric hand-object interactions.
In this paper, we obtain the <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L Superscript p"> <mml:semantics> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:annotation encoding="application/x-tex">L^p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> restriction estimates for the truncated conic … In this paper, we obtain the <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L Superscript p"> <mml:semantics> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:annotation encoding="application/x-tex">L^p</mml:annotation> </mml:semantics> </mml:math> </inline-formula> restriction estimates for the truncated conic surface <disp-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Sigma equals StartSet left-parenthesis xi prime comma xi Subscript n Baseline comma minus xi Subscript n Superscript negative 1 Baseline mathematical left-angle xi prime comma upper N xi Superscript prime Baseline mathematical right-angle right-parenthesis colon left-parenthesis xi prime comma xi Subscript n Baseline right-parenthesis element-of upper B Superscript n minus 1 Baseline left-parenthesis 0 comma 1 right-parenthesis times left-bracket 1 comma 2 right-bracket EndSet"> <mml:semantics> <mml:mrow> <mml:mi mathvariant="normal">Σ<!-- Σ --></mml:mi> <mml:mo>=</mml:mo> <mml:mstyle scriptlevel="0"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo maxsize="1.2em" minsize="1.2em">{</mml:mo> </mml:mrow> </mml:mstyle> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mi>n</mml:mi> </mml:msub> <mml:mo>,</mml:mo> <mml:mo>−<!-- − --></mml:mo> <mml:msubsup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mi>n</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−<!-- − --></mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo fence="false" stretchy="false">⟨<!-- ⟨ --></mml:mo> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:mi>N</mml:mi> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo fence="false" stretchy="false">⟩<!-- ⟩ --></mml:mo> <mml:mo stretchy="false">)</mml:mo> <mml:mo>:</mml:mo> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>ξ<!-- ξ --></mml:mi> <mml:mi>n</mml:mi> </mml:msub> <mml:mo stretchy="false">)</mml:mo> <mml:mo>∈<!-- ∈ --></mml:mo> <mml:msup> <mml:mi>B</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>n</mml:mi> <mml:mo>−<!-- − --></mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy="false">)</mml:mo> <mml:mo>×<!-- × --></mml:mo> <mml:mo stretchy="false">[</mml:mo> <mml:mn>1</mml:mn> <mml:mo>,</mml:mo> <mml:mn>2</mml:mn> <mml:mo stretchy="false">]</mml:mo> <mml:mstyle scriptlevel="0"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo maxsize="1.2em" minsize="1.2em">}</mml:mo> </mml:mrow> </mml:mstyle> </mml:mrow> <mml:annotation encoding="application/x-tex">\begin{equation*} \Sigma =\big \{(\xi ’,\xi _n,-\xi _n^{-1}\langle \xi ’,N\xi ’\rangle ): (\xi ’,\xi _n)\in B^{n-1}(0,1)\times [1,2]\big \} \end{equation*}</mml:annotation> </mml:semantics> </mml:math> </disp-formula> with <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper N equals upper I Subscript n minus 1 minus m Baseline circled-plus left-parenthesis minus upper I Subscript m Baseline right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mi>N</mml:mi> <mml:mo>=</mml:mo> <mml:msub> <mml:mi>I</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>n</mml:mi> <mml:mo>−<!-- − --></mml:mo> <mml:mn>1</mml:mn> <mml:mo>−<!-- − --></mml:mo> <mml:mi>m</mml:mi> </mml:mrow> </mml:msub> <mml:mo>⊕<!-- ⊕ --></mml:mo> <mml:mo stretchy="false">(</mml:mo> <mml:mo>−<!-- − --></mml:mo> <mml:msub> <mml:mi>I</mml:mi> <mml:mi>m</mml:mi> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">N=I_{n-1-m}\oplus (-I_m)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> for <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="m less-than-or-equal-to left floor StartFraction n minus 3 Over 2 EndFraction right floor"> <mml:semantics> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>≤<!-- ≤ --></mml:mo> <mml:mo fence="false" stretchy="false">⌊<!-- ⌊ --></mml:mo> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mfrac> <mml:mrow> <mml:mi>n</mml:mi> <mml:mo>−<!-- − --></mml:mo> <mml:mn>3</mml:mn> </mml:mrow> <mml:mn>2</mml:mn> </mml:mfrac> </mml:mstyle> <mml:mo fence="false" stretchy="false">⌋<!-- ⌋ --></mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">m\leq \lfloor \tfrac {n-3}2\rfloor</mml:annotation> </mml:semantics> </mml:math> </inline-formula> provided <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="p greater-than StartFraction 2 left-parenthesis n plus 3 right-parenthesis Over n plus 1 EndFraction"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mstyle displaystyle="false" scriptlevel="0"> <mml:mfrac> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mi>n</mml:mi> <mml:mo>+</mml:mo> <mml:mn>3</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>n</mml:mi> <mml:mo>+</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:mfrac> </mml:mstyle> </mml:mrow> <mml:annotation encoding="application/x-tex">p&gt;\tfrac {2(n+3)}{n+1}</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. The main ingredients of the proof are the bilinear estimates of strongly separated property and a geometric distribution about caps.
Recently, the sharp <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L squared"> <mml:semantics> <mml:msup> <mml:mi>L</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:annotation encoding="application/x-tex">L^2</mml:annotation> </mml:semantics> </mml:math> </inline-formula>-bilinear (adjoint) restriction estimates for the cone and the paraboloid were … Recently, the sharp <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L squared"> <mml:semantics> <mml:msup> <mml:mi>L</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:annotation encoding="application/x-tex">L^2</mml:annotation> </mml:semantics> </mml:math> </inline-formula>-bilinear (adjoint) restriction estimates for the cone and the paraboloid were established by Wolff and Tao, respectively. Their results rely on the fact that for the cone and the paraboloid, the nonzero principal curvatures have the same sign. We generalize those bilinear restriction estimates to surfaces with curvatures of different signs.
The purpose of this paper is to prove an essentially sharp L^2 Fourier restriction estimate for light cones, of the type which is called bilinear in the recent literature. The purpose of this paper is to prove an essentially sharp L^2 Fourier restriction estimate for light cones, of the type which is called bilinear in the recent literature.
Let \mathbb{H} be a (d-1) -dimensional hyperbolic paraboloid in \mathbb{R}^d and let Ef be the Fourier extension operator associated to \mathbb{H} , with f supported in B^{d-1}(0,2) . We prove … Let \mathbb{H} be a (d-1) -dimensional hyperbolic paraboloid in \mathbb{R}^d and let Ef be the Fourier extension operator associated to \mathbb{H} , with f supported in B^{d-1}(0,2) . We prove that \lVert Ef \rVert_{L^p (B(0,R))} \leq C_{\varepsilon}R^{\varepsilon}\lVert f \rVert_{L^p} for all p \geq 2(d+2)/d whenever d/2\geq m + 1 , where m is the minimum between the number of positive and negative principal curvatures of \mathbb{H} . Bilinear restriction estimates for \mathbb{H} proved by S. Lee and Vargas play an important role in our argument.
We obtain an improved Fourier restriction estimate for a truncated cone using the method of polynomial partitioning in dimension n\geq 3 , which in particular solves the cone restriction conjecture … We obtain an improved Fourier restriction estimate for a truncated cone using the method of polynomial partitioning in dimension n\geq 3 , which in particular solves the cone restriction conjecture for n=5 , and recovers the sharp range for 3\leq n\leq 4 . The main ingredient of the proof is a k -broad estimate for the cone extension operator, which is a weak version of the k -linear cone restriction conjecture for 2\leq k\leq n .
If f is a function supported on the truncated paraboloid in R3 and E is the corresponding extension operator, then we prove that for all p>3+3∕13, ‖Ef‖Lp(R3)≤C‖f‖L∞. The proof combines … If f is a function supported on the truncated paraboloid in R3 and E is the corresponding extension operator, then we prove that for all p>3+3∕13, ‖Ef‖Lp(R3)≤C‖f‖L∞. The proof combines Wolff's two ends argument with polynomial partitioning techniques. We also observe some geometric structures in the wave packets.
We improve the estimates in the restriction problem in dimension $n \geqslant 4$. To do so, we establish a weak version of a $k$-linear restriction estimate for any $k$. The … We improve the estimates in the restriction problem in dimension $n \geqslant 4$. To do so, we establish a weak version of a $k$-linear restriction estimate for any $k$. The exponents in this weak $k$-linear estimate are sharp for all $k$ and $n$.
Let <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Gamma"> <mml:semantics> <mml:mi mathvariant="normal">Γ<!-- Γ --></mml:mi> <mml:annotation encoding="application/x-tex">\Gamma</mml:annotation> </mml:semantics> </mml:math> </inline-formula> be the surface of a circular cone in <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" … Let <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Gamma"> <mml:semantics> <mml:mi mathvariant="normal">Γ<!-- Γ --></mml:mi> <mml:annotation encoding="application/x-tex">\Gamma</mml:annotation> </mml:semantics> </mml:math> </inline-formula> be the surface of a circular cone in <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="bold upper R cubed"> <mml:semantics> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">R</mml:mi> </mml:mrow> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> </mml:mrow> <mml:annotation encoding="application/x-tex">{{\mathbf {R}}^3}</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. We show that if <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="1 less-than-or-slanted-equals p greater-than 4 slash 3"> <mml:semantics> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>⩽<!-- ⩽ --></mml:mo> <mml:mi>p</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>4</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> <mml:annotation encoding="application/x-tex">1 \leqslant p &gt; 4/3</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="1 slash q equals 3 left-parenthesis 1 minus 1 slash p right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mn>1</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi>q</mml:mi> <mml:mo>=</mml:mo> <mml:mn>3</mml:mn> <mml:mo stretchy="false">(</mml:mo> <mml:mn>1</mml:mn> <mml:mo>−<!-- − --></mml:mo> <mml:mn>1</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi>p</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">1/q = 3(1 - 1/p)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> and <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="f element-of upper L Superscript p Baseline left-parenthesis bold upper R cubed right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mi>f</mml:mi> <mml:mo>∈<!-- ∈ --></mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">R</mml:mi> </mml:mrow> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">f \in {L^p}({{\mathbf {R}}^3})</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, then the Fourier transform of <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="f"> <mml:semantics> <mml:mi>f</mml:mi> <mml:annotation encoding="application/x-tex">f</mml:annotation> </mml:semantics> </mml:math> </inline-formula> belongs to <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L Superscript q Baseline left-parenthesis normal upper Gamma comma d sigma right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>q</mml:mi> </mml:msup> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mi mathvariant="normal">Γ<!-- Γ --></mml:mi> <mml:mo>,</mml:mo> <mml:mi>d</mml:mi> <mml:mi>σ<!-- σ --></mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">{L^q}(\Gamma ,d\sigma )</mml:annotation> </mml:semantics> </mml:math> </inline-formula> for a certain natural measure <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="sigma"> <mml:semantics> <mml:mi>σ<!-- σ --></mml:mi> <mml:annotation encoding="application/x-tex">\sigma</mml:annotation> </mml:semantics> </mml:math> </inline-formula> on <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Gamma"> <mml:semantics> <mml:mi mathvariant="normal">Γ<!-- Γ --></mml:mi> <mml:annotation encoding="application/x-tex">\Gamma</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. Following P. Tomas we also establish bounds for restrictions of Fourier transforms to conic annuli at the endpoint <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="p equals 4 slash 3"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:mn>4</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> <mml:annotation encoding="application/x-tex">p = 4/3</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, with logarithmic growth of the bound as the thickness of the annulus tends to zero.
If <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper S"> <mml:semantics> <mml:mi>S</mml:mi> <mml:annotation encoding="application/x-tex">S</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is a smooth compact surface in <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper R cubed"> <mml:semantics> <mml:msup> … If <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper S"> <mml:semantics> <mml:mi>S</mml:mi> <mml:annotation encoding="application/x-tex">S</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is a smooth compact surface in <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper R cubed"> <mml:semantics> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">R</mml:mi> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> <mml:annotation encoding="application/x-tex">\mathbb {R}^3</mml:annotation> </mml:semantics> </mml:math> </inline-formula> with strictly positive second fundamental form, and <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper E Subscript upper S"> <mml:semantics> <mml:msub> <mml:mi>E</mml:mi> <mml:mi>S</mml:mi> </mml:msub> <mml:annotation encoding="application/x-tex">E_S</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is the corresponding extension operator, then we prove that for all <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="p greater-than 3.25"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>3.25</mml:mn> </mml:mrow> <mml:annotation encoding="application/x-tex">p &gt; 3.25</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar upper E Subscript upper S Baseline f double-vertical-bar Subscript upper L Sub Superscript p Subscript left-parenthesis double-struck upper R cubed right-parenthesis Baseline less-than-or-equal-to upper C left-parenthesis p comma upper S right-parenthesis double-vertical-bar f double-vertical-bar Subscript upper L Sub Superscript normal infinity Subscript left-parenthesis upper S right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mo fence="false" stretchy="false">‖<!-- ‖ --></mml:mo> <mml:msub> <mml:mi>E</mml:mi> <mml:mi>S</mml:mi> </mml:msub> <mml:mi>f</mml:mi> <mml:msub> <mml:mo fence="false" stretchy="false">‖<!-- ‖ --></mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">R</mml:mi> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:msub> <mml:mo>≤<!-- ≤ --></mml:mo> <mml:mi>C</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>p</mml:mi> <mml:mo>,</mml:mo> <mml:mi>S</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mo fence="false" stretchy="false">‖<!-- ‖ --></mml:mo> <mml:mi>f</mml:mi> <mml:msub> <mml:mo fence="false" stretchy="false">‖<!-- ‖ --></mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mi>L</mml:mi> <mml:mi mathvariant="normal">∞<!-- ∞ --></mml:mi> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:mi>S</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> <mml:annotation encoding="application/x-tex">\| E_S f\|_{L^p(\mathbb {R}^3)} \le C(p,S) \| f \|_{L^\infty (S)}</mml:annotation> </mml:semantics> </mml:math> </inline-formula>. The proof uses polynomial partitioning arguments from incidence geometry.
Let ƒ be a Schwartz function on R n , and let ƒ(0) denote the restriction of the Fourier transform of ƒ to the unit sphere S n ~x in … Let ƒ be a Schwartz function on R n , and let ƒ(0) denote the restriction of the Fourier transform of ƒ to the unit sphere S n ~x in R n .We prove THEOREM.Iff is in L p (R n ) for some p with 1 < p < 2(n +1)/(« + 3), then 5 s n-i\Ke)\ 2 de<c p \\f\\ 2 p .PROOF.Jl/(0)l 2 d0 = ƒƒ* f(x)fà(x)dx = fmdè*f(x)dx<\\f\\ p \\âd *f\\ p , for conjugate indices p and p .Thus it suffices to prove that the operator given by convolution with *3$ is bounded from LP to LP for p in the appropriate range.Let K(x) be a radial Schwartz function with K(x) = 1 for \x\ < 100, and let).It suffices to show there exists e = e(p) > 0 such that \\T k * ƒ \\ p , < C2~€ fc || ƒ || p .This follows from interpolating the estimates \\T k * ƒ IL < C2-( "~1>*/ 2 || f\\ x and ||r fc *f\\ 2 < 2 k \\f\\ 2 .Professor E. M. Stein has extended the range of this result to include p = 2(n + l)/(n + 3).His proof uses complex interpolation of the operators given by convolution with the functions B a (x) = J 0 (27t\x\)/\x\°.Then A great deal was previously known about such restriction theorems.E. M. Stein originally established the theorem for 1 </? < 4n/(3n + 1).For n = 2, this was extended by Fefferman and Stein [2] to the range 1 < p < 6/5.P. Sjolin (see [1]) proved the theorem for n = 3 and 1 <p < 4/3.Finally, A. Zygmund [3] determined for two dimensions all p and q such that the Fourier transform of an LP function restricts to L q (S x ).Since a
We prove an abstract Strichartz estimate, which implies previously unknown endpoint Strichartz estimates for the wave equation (in dimension n ≥ 4) and the Schrödinger equation (in dimension n ≥ … We prove an abstract Strichartz estimate, which implies previously unknown endpoint Strichartz estimates for the wave equation (in dimension n ≥ 4) and the Schrödinger equation (in dimension n ≥ 3). Three other applications are discussed: local existence for a nonlinear wave equation; and Strichartz-type estimates for more general dispersive equations and for the kinetic transport equation.
Bilinear restriction estimates have appeared in work of Bourgain, Klainerman, and Machedon. In this paper we develop the theory of these estimates (together with the analogues for Kakeya estimates). As … Bilinear restriction estimates have appeared in work of Bourgain, Klainerman, and Machedon. In this paper we develop the theory of these estimates (together with the analogues for Kakeya estimates). As a consequence we improve the <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis upper L Superscript p Baseline comma upper L Superscript p Baseline right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:mo>,</mml:mo> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">(L^p,L^p)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> spherical restriction theorem of Wolff from <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="p greater-than 42 slash 11"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>42</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mn>11</mml:mn> </mml:mrow> <mml:annotation encoding="application/x-tex">p &gt; 42/11</mml:annotation> </mml:semantics> </mml:math> </inline-formula> to <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="p greater-than 34 slash 9"> <mml:semantics> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>34</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mn>9</mml:mn> </mml:mrow> <mml:annotation encoding="application/x-tex">p &gt; 34/9</mml:annotation> </mml:semantics> </mml:math> </inline-formula>, and also obtain a sharp <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis upper L Superscript p Baseline comma upper L Superscript q Baseline right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>p</mml:mi> </mml:msup> <mml:mo>,</mml:mo> <mml:msup> <mml:mi>L</mml:mi> <mml:mi>q</mml:mi> </mml:msup> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">(L^p,L^q)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> spherical restriction theorem for <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="q greater-than 4 minus five twenty-sevenths"> <mml:semantics> <mml:mrow> <mml:mi>q</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>4</mml:mn> <mml:mo>−<!-- − --></mml:mo> <mml:mfrac> <mml:mn>5</mml:mn> <mml:mn>27</mml:mn> </mml:mfrac> </mml:mrow> <mml:annotation encoding="application/x-tex">q&gt; 4 - \frac {5}{27}</mml:annotation> </mml:semantics> </mml:math> </inline-formula>.
We prove a maximal Fourier restriction theorem for hypersurfaces in \(\mathbb{R}^{d}\) for any dimension \(d\geq 3\) in a restricted range of exponents given by the Tomas-Stein theorem (spheres being the … We prove a maximal Fourier restriction theorem for hypersurfaces in \(\mathbb{R}^{d}\) for any dimension \(d\geq 3\) in a restricted range of exponents given by the Tomas-Stein theorem (spheres being the most canonical example). The proof consists of a simple observation. When \(d=3\) the range corresponds exactly to the full Tomas-Stein one, but is otherwise a proper subset when \(d&gt;3\). We also present an application regarding the Lebesgue points of functions in \(\mathcal{F}(L^p)\) when \(p\) is sufficiently close to 1.
Fourier restriction theorems, whose study had been initiated by E.M. Stein, usually describe a family of a priori estimates of the L^q -norm of the restriction of the Fourier transform … Fourier restriction theorems, whose study had been initiated by E.M. Stein, usually describe a family of a priori estimates of the L^q -norm of the restriction of the Fourier transform of a function f in L^p(\mathbb R^n) to a given subvariety S , endowed with a suitable measure. Such estimates allow to define the restriction \mathcal{R} f of the Fourier transform of an L^p -function to S in an operator theoretic sense. In this article, we begin to investigate the question what is the „intrinsic" pointwise relation between \mathcal{R} f and the Fourier transform of f , by looking at curves in the plane, for instance with non-vanishing curvature. To this end, we bound suitable maximal operators, including the Hardy–Littlewood maximal function of the Fourier transform of f restricted to S .
We establish variational estimates related to the problem of restricting the Fourier transform of a three-dimensional function to the two-dimensional Euclidean sphere. At the same time, we give a short … We establish variational estimates related to the problem of restricting the Fourier transform of a three-dimensional function to the two-dimensional Euclidean sphere. At the same time, we give a short survey of the recent field of maximal Fourier restriction theory.
We show that, for $n\ge 3$, $\mathrm{lim}_{t\to 0} e^{it\Delta} f(x) f(x)$ holds almost everywhere for all $f\in H^s(\mathbb{R}^n)$ provided that $s> \frac{n}{2(n+1)}$. Due to a counterexample by Bourgain, up to … We show that, for $n\ge 3$, $\mathrm{lim}_{t\to 0} e^{it\Delta} f(x) f(x)$ holds almost everywhere for all $f\in H^s(\mathbb{R}^n)$ provided that $s> \frac{n}{2(n+1)}$. Due to a counterexample by Bourgain, up to the endpoint, this result is sharp and fully resolves a problem raised by Carleson. Our main theorem is a fractal $L^2$ restriction estimate, which also gives improved results on the size of the divergence set of the Schrödinger solutions, the Falconer distance set problem and the spherical average Fourier decay rates of fractal measures. The key ingredients of the proof include multilinear Kakeya estimates, decoupling and induction on scales.
We prove an endpoint version of the Stein-Tomas restriction theorem, for a general class of measures, and with a strengthened Lorentz space estimate.A similar improvement is obtained for Stein's estimate … We prove an endpoint version of the Stein-Tomas restriction theorem, for a general class of measures, and with a strengthened Lorentz space estimate.A similar improvement is obtained for Stein's estimate on oscillatory integrals of Carleson-Sjölin-Hörmander type and some spectral projection operators on compact manifolds, and for classes of oscillatory integral operators with one-sided fold singularities.
We prove a class of modified paraboloid restriction estimates with a loss of angular derivatives for the full set of paraboloid restriction conjecture indices. This result generalizes the paraboloid restriction … We prove a class of modified paraboloid restriction estimates with a loss of angular derivatives for the full set of paraboloid restriction conjecture indices. This result generalizes the paraboloid restriction estimate in radial case from [Shao, Rev. Mat. Iberoam. 25(2009), 1127–1168], as well as the result from [Miao et al. Proc. AMS 140(2012), 2091–2102]. As an application, we show a local smoothing estimate for a solution of the linear Schrödinger equation under the assumption that the initial datum has additional angular regularity.
In contrast to elliptic surfaces, the Fourier restriction problem for hypersurfaces of non-vanishing Gaussian curvature which admit principal curvatures of opposite signs is still hardly understood. In fact, even for … In contrast to elliptic surfaces, the Fourier restriction problem for hypersurfaces of non-vanishing Gaussian curvature which admit principal curvatures of opposite signs is still hardly understood. In fact, even for 2-surfaces, the only case of a hyperbolic surface for which Fourier restriction estimates could be established that are analogous to the ones known for elliptic surfaces is the hyperbolic paraboloid or 'saddle' z = x y . The bilinear method gave here sharp results for p > 10 / 3 , and this result was recently improved to p > 3.25 . This paper aims to be the first step in extending those results to more general hyperbolic surfaces. We consider a specific cubic perturbation of the saddle and obtain the sharp result, up to the endpoint, for p > 10 / 3 . In the application of the bilinear method, we show that the behavior at small scales in our surface is drastically different from the saddle. Indeed, as it turns out, in some regimes the perturbation term assumes a dominant role, which necessitates the introduction of a number of new techniques that should also be useful for the study of more general hyperbolic surfaces. This specific perturbation has turned out to be of fundamental importance also to the understanding of more general classes of perturbations.
We consider Guth's approach to the Fourier restriction problem via polynomial partitioning.By writing out his induction argument as a recursive algorithm and introducing new geometric information, known as the polynomial … We consider Guth's approach to the Fourier restriction problem via polynomial partitioning.By writing out his induction argument as a recursive algorithm and introducing new geometric information, known as the polynomial Wolff axioms, we obtain improved bounds for the restriction conjecture, particularly in high dimensions.Consequences for the Kakeya conjecture are also considered.
We prove inequalities concerning the restriction of the strong maximal function of the Fourier transform to the circle, providing an answer to a question left open by Müller, Ricci, and … We prove inequalities concerning the restriction of the strong maximal function of the Fourier transform to the circle, providing an answer to a question left open by Müller, Ricci, and Wright. We employ methods similar in spirit to the classical proofs of the two-dimensional restriction theorem, with the addition of a suitable trick to help us linearise our maximal function. In the end, we comment on how to use the same linearisation trick in combination with Vitturi’s duality argument to obtain sharper high-dimensional results for the Hardy–Littlewood maximal function.
2 ) Given a (possibly empty) list of objects L, for real numbers Ap, Bp 0 depending on some Lebesgue exponent p, the notation Ap L Bp or Bp L … 2 ) Given a (possibly empty) list of objects L, for real numbers Ap, Bp 0 depending on some Lebesgue exponent p, the notation Ap L Bp or Bp L Ap signifies that Ap CBp for some constant C =C L,n,p 0 depending on the objects in the list, n and p.In addition, Ap ∼ L Bp is used to signify that Ap L Bp and Ap L Bp.( 4 ) In particular, Lee [19] proved that for positive-definite phases (1.4) holds for p 2(n+2)/n in all dimensions, extending the range in Theorem 1.1 when n is odd.( 7 ) The connection with Bochner-Riesz multipliers is made via the classical reduction of Carleson-Sjölin [10], [17], as discussed in the previous subsection.
Abstract We consider a surface with negative curvature in $${{\mathbb {R}}}^3,$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> <mml:mo>,</mml:mo> </mml:mrow> </mml:math> which is a cubic perturbation of the … Abstract We consider a surface with negative curvature in $${{\mathbb {R}}}^3,$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> <mml:mo>,</mml:mo> </mml:mrow> </mml:math> which is a cubic perturbation of the saddle. For this surface, we prove a new restriction theorem, analogous to the theorem for paraboloids proved by L. Guth in 2016. This specific perturbation has turned out to be of fundamental importance also to the understanding of more general classes of one-variate perturbations, and we hope that the present paper will further help to pave the way for the study of general perturbations of the saddle by means of the polynomial partitioning method.
Abstract We prove Fourier restriction estimates by means of the polynomial partitioning method for compact subsets of any sufficiently smooth hyperbolic hypersurface in $$\mathbb {R}^3.$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow> … Abstract We prove Fourier restriction estimates by means of the polynomial partitioning method for compact subsets of any sufficiently smooth hyperbolic hypersurface in $$\mathbb {R}^3.$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> <mml:mo>.</mml:mo> </mml:mrow> </mml:math> Our approach exploits in a crucial way the underlying hyperbolic geometry, which leads to a novel notion of strong transversality and corresponding “exceptional” sets. For the division of these exceptional sets we make crucial and perhaps surprising use of a lemma on level sets for sufficiently smooth one-variate functions from a previous article of ours.
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We study the generalization of the Falconer distance problem to the Riemannian setting. In particular, we extend the result of Guth--Iosevich--Ou--Wang for the distance set in the plane to general … We study the generalization of the Falconer distance problem to the Riemannian setting. In particular, we extend the result of Guth--Iosevich--Ou--Wang for the distance set in the plane to general Riemannian surfaces. Key new ingredients include a family of refined microlocal decoupling inequalities, which are related to the work of Beltran--Hickman--Sogge on Wolff-type inequalities, and an analog of Orponen's radial projection lemma which has proved quite useful in recent work on distance sets.
We prove a general Stein-Tomas type restriction theorem for measures of given dimension and Fourier exponent. We prove a general Stein-Tomas type restriction theorem for measures of given dimension and Fourier exponent.
We prove that for a finite type curve in ℝ3 the maximal operator generated by dilations is bounded on Lp for sufficiently large p. We also show the endpoint Lp … We prove that for a finite type curve in ℝ3 the maximal operator generated by dilations is bounded on Lp for sufficiently large p. We also show the endpoint Lp → Lp1/p regularity result for the averaging operators for large p. The proofs make use of a deep result of Thomas Wolff about decompositions of cone multipliers.