<p>Let <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\((a_n)_{n \in \mathbb {N}}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mo stretchy="false">(</mo> <msub> <mi>a</mi> <mi>n</mi> </msub> <mo stretchy="false">)</mo> </mrow> <mrow> <mi>n</mi> <mo>∈</mo> <mi mathvariant="double-struck">N</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> be a lacunary sequence of integers satisfying the Hadamard gap condition. For any fixed dimension <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(d \ge 1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>d</mi> <mo>≥</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>, we establish asymptotic upper bounds for the maximal gap in the set of dilates <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\{\varvec{\alpha }a_n \}_{n \le N}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mo stretchy="false">{</mo> <mrow> <mi mathvariant="bold-italic">α</mi> </mrow> <msub> <mi>a</mi> <mi>n</mi> </msub> <mo stretchy="false">}</mo> </mrow> <mrow> <mi>n</mi> <mo>≤</mo> <mi>N</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> modulo 1 as <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(N \rightarrow \infty \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>N</mi> <mo stretchy="false">→</mo> <mi>∞</mi> </mrow> </math></EquationSource> </InlineEquation>, for Lebesgue–almost all dilation vectors <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\varvec{\alpha }\in [0,1]^d\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mrow> <mi mathvariant="bold-italic">α</mi> </mrow> <mo>∈</mo> <msup> <mrow> <mo stretchy="false">[</mo> <mn>0</mn> <mo>,</mo> <mn>1</mn> <mo stretchy="false">]</mo> </mrow> <mi>d</mi> </msup> </mrow> </math></EquationSource> </InlineEquation>. More precisely, we prove that for any lacunary <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\((a_n)_{n \in \mathbb {N}}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mo stretchy="false">(</mo> <msub> <mi>a</mi> <mi>n</mi> </msub> <mo stretchy="false">)</mo> </mrow> <mrow> <mi>n</mi> <mo>∈</mo> <mi mathvariant="double-struck">N</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> and Lebesgue–almost all <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\varvec{\alpha }\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="bold-italic">α</mi> </mrow> </math></EquationSource> </InlineEquation>, every convex set in <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\([0,1]^d\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mo stretchy="false">[</mo> <mn>0</mn> <mo>,</mo> <mn>1</mn> <mo stretchy="false">]</mo> </mrow> <mi>d</mi> </msup> </math></EquationSource> </InlineEquation> of volume at least <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\((\log N)^{2}/N\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mrow> <mo stretchy="false">(</mo> <mo>log</mo> <mi>N</mi> <mo stretchy="false">)</mo> </mrow> <mn>2</mn> </msup> <mo stretchy="false">/</mo> <mi>N</mi> </mrow> </math></EquationSource> </InlineEquation> must contain an element of the set <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(\{\varvec{\alpha }a_n \}_{n \le N}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mo stretchy="false">{</mo> <mrow> <mi mathvariant="bold-italic">α</mi> </mrow> <msub> <mi>a</mi> <mi>n</mi> </msub> <mo stretchy="false">}</mo> </mrow> <mrow> <mi>n</mi> <mo>≤</mo> <mi>N</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> mod 1, for all sufficiently large <i>N</i>. We also establish a generalized version of this result, where the <i>d</i>-dimensional Lebesgue measure is replaced by a general measure satisfying a certain Fourier decay condition. Our result is optimal up to logarithmic factors, and recovers as a special case a recent result for dimension <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(d=1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>d</mi> <mo>=</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>.</p>

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On the maximal volume of empty convex bodies amidst multivariate dilates of a lacunary integer sequence

  • Eduard Stefanescu

摘要

Let \((a_n)_{n \in \mathbb {N}}\) ( a n ) n N be a lacunary sequence of integers satisfying the Hadamard gap condition. For any fixed dimension \(d \ge 1\) d 1 , we establish asymptotic upper bounds for the maximal gap in the set of dilates \(\{\varvec{\alpha }a_n \}_{n \le N}\) { α a n } n N modulo 1 as \(N \rightarrow \infty \) N , for Lebesgue–almost all dilation vectors \(\varvec{\alpha }\in [0,1]^d\) α [ 0 , 1 ] d . More precisely, we prove that for any lacunary \((a_n)_{n \in \mathbb {N}}\) ( a n ) n N and Lebesgue–almost all \(\varvec{\alpha }\) α , every convex set in \([0,1]^d\) [ 0 , 1 ] d of volume at least \((\log N)^{2}/N\) ( log N ) 2 / N must contain an element of the set \(\{\varvec{\alpha }a_n \}_{n \le N}\) { α a n } n N mod 1, for all sufficiently large N. We also establish a generalized version of this result, where the d-dimensional Lebesgue measure is replaced by a general measure satisfying a certain Fourier decay condition. Our result is optimal up to logarithmic factors, and recovers as a special case a recent result for dimension \(d=1\) d = 1 .