<p>In this paper we introduce spaces of <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(BLO \)</EquationSource> </InlineEquation>-type related to Laguerre polynomial expansions. We consider the probability measure on <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\((0,\infty )\)</EquationSource> </InlineEquation> defined by <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(d\gamma _\alpha (x)=\frac{2}{\Gamma (\alpha +1)}e^{-x^2}x^{2\alpha +1}dx\)</EquationSource> </InlineEquation> with <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\alpha &gt;-\frac{1}{2}\)</EquationSource> </InlineEquation>. For every <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(a&gt;0\)</EquationSource> </InlineEquation>, the space <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(BLO _a((0,\infty ),\gamma _\alpha )\)</EquationSource> </InlineEquation> consists of all those measurable functions defined on <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\((0,\infty )\)</EquationSource> </InlineEquation> having bounded lower oscillation with respect to <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\gamma _\alpha \)</EquationSource> </InlineEquation> over an admissible family <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(\mathcal {B}_a\)</EquationSource> </InlineEquation> of intervals in <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\((0,\infty )\)</EquationSource> </InlineEquation>. The space <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(BLO _a((0,\infty ),\gamma _\alpha )\)</EquationSource> </InlineEquation> is a subspace of the space <InlineEquation ID="IEq12"> <EquationSource Format="TEX">\(BMO _a((0,\infty ),\gamma _\alpha )\)</EquationSource> </InlineEquation> of bounded mean oscillation functions with respect to <InlineEquation ID="IEq13"> <EquationSource Format="TEX">\(\gamma _\alpha \)</EquationSource> </InlineEquation> and <InlineEquation ID="IEq14"> <EquationSource Format="TEX">\(\mathcal {B}_a\)</EquationSource> </InlineEquation>. The natural <i>a</i>-local centered maximal function defined by <InlineEquation ID="IEq15"> <EquationSource Format="TEX">\(\gamma _\alpha \)</EquationSource> </InlineEquation> is bounded from <InlineEquation ID="IEq16"> <EquationSource Format="TEX">\(BMO _a((0,\infty ),\gamma _\alpha )\)</EquationSource> </InlineEquation> into <InlineEquation ID="IEq17"> <EquationSource Format="TEX">\(BLO _a((0,\infty ),\gamma _\alpha )\)</EquationSource> </InlineEquation>. We prove that the maximal operator, the <InlineEquation ID="IEq18"> <EquationSource Format="TEX">\(\rho \)</EquationSource> </InlineEquation>-variation and the oscillation operators associated with local truncations of the Riesz transforms in the Laguerre setting are bounded from <InlineEquation ID="IEq19"> <EquationSource Format="TEX">\(L^\infty ((0,\infty ),\gamma _\alpha )\)</EquationSource> </InlineEquation> into <InlineEquation ID="IEq20"> <EquationSource Format="TEX">\(BLO _a((0,\infty ),\gamma _\alpha )\)</EquationSource> </InlineEquation>. Also, we obtain a similar result for the maximal operator of local truncations for spectral Laplace transform type multipliers.</p>

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BLO spaces associated with Laguerre polynomial expansions

  • Jorge J. Betancor,
  • Estefanía Dalmasso,
  • Pablo Quijano

摘要

In this paper we introduce spaces of \(BLO \) -type related to Laguerre polynomial expansions. We consider the probability measure on \((0,\infty )\) defined by \(d\gamma _\alpha (x)=\frac{2}{\Gamma (\alpha +1)}e^{-x^2}x^{2\alpha +1}dx\) with \(\alpha >-\frac{1}{2}\) . For every \(a>0\) , the space \(BLO _a((0,\infty ),\gamma _\alpha )\) consists of all those measurable functions defined on \((0,\infty )\) having bounded lower oscillation with respect to \(\gamma _\alpha \) over an admissible family \(\mathcal {B}_a\) of intervals in \((0,\infty )\) . The space \(BLO _a((0,\infty ),\gamma _\alpha )\) is a subspace of the space \(BMO _a((0,\infty ),\gamma _\alpha )\) of bounded mean oscillation functions with respect to \(\gamma _\alpha \) and \(\mathcal {B}_a\) . The natural a-local centered maximal function defined by \(\gamma _\alpha \) is bounded from \(BMO _a((0,\infty ),\gamma _\alpha )\) into \(BLO _a((0,\infty ),\gamma _\alpha )\) . We prove that the maximal operator, the \(\rho \) -variation and the oscillation operators associated with local truncations of the Riesz transforms in the Laguerre setting are bounded from \(L^\infty ((0,\infty ),\gamma _\alpha )\) into \(BLO _a((0,\infty ),\gamma _\alpha )\) . Also, we obtain a similar result for the maximal operator of local truncations for spectral Laplace transform type multipliers.