Logarithmic summability of Fourier series.
Look-ahead Levinson- and Schur-type recurrences in the Padé table.
L'orthogonalité et les récurrences de polynômes d'ordre supérieur à deux
Lp bounds for Hilbert transforms along convex curves.
Lp bounds for Riesz transforms and square roots associated to second order elliptic operators.
Lp estimates for singular integrals with kernels beloging to certain block spaces.
We establish the Lp boundedness of singular integrals with kernels which belong to block spaces and are supported by subvarities.
Lp extremal polynomials. Results and perspectives
2000 Mathematics Subject Classification: 30C40, 30D50, 30E10, 30E15, 42C05.Let α = β+γ be a positive finite measure defined on the Borel sets of C, with compact support, where β is a measure concentrated on a closed Jordan curve or on an arc (a circle or a segment) and γ is a discrete measure concentrated on an infinite number of points. In this survey paper, we present a synthesis on the asymptotic behaviour of orthogonal polynomials or Lp extremal polynomials associated to the measure α. We analyze...
LP → LQ - Estimates for the Fractional Acoustic Potentials and some Related Operators
Mathematics Subject Classification: 47B38, 31B10, 42B20, 42B15.We obtain the Lp → Lq - estimates for the fractional acoustic potentials in R^n, which are known to be negative powers of the Helmholtz operator, and some related operators. Some applications of these estimates are also given.* This paper has been supported by Russian Fond of Fundamental Investigations under Grant No. 40–01–008632 a.
Lp multipliers and their H1-L1 estimates on the Heisenberg group.
We give a Hörmander-type sufficient condition on an operator-valued function M that implies the Lp-boundedness result for the operator TM defined by (TMf)^ = Mf^ on the (2n + 1)-dimensional Heisenberg group Hn. Here ^ denotes the Fourier transform on Hn defined in terms of the Fock representations. We also show the H1-L1 boundedness of TM, ||TMf||L1 ≤ C||f||H1, for Hn under the same hypotheses of Lp-boundedness.
Lp-Abschätzungen und klassische Lösungen für nichtlineare Wellengleichungen. I.
Lp-bounds for spherical maximal operators on Zn.
We prove analogue statements of the spherical maximal theorem of E. M. Stein, for the lattice points Zn. We decompose the discrete spherical measures as an integral of Gaussian kernels st,ε(x) = e2πi|x|2(t + iε). By using Minkowski's integral inequality it is enough to prove Lp-bounds for the corresponding convolution operators. The proof is then based on L2-estimates by analysing the Fourier transforms ^st,ε(ξ), which can be handled by making use of the circle method for exponential sums. As a...
Lₚ-deviations from zero of polynomials with integral coefficients
Lp-estimates for Oscillatory Integrals in Several Variables.
Lp-Improving Properties for Some Measures Supported on Curves.
Majoration de la transformée de Fourier de certaines mesures
Soit une fonction polynôme de dans . On considère la mesure sur le graphe de dont la projection sur est la mesure de Lebesgue. On étudie ici le comportement de la transformée de Fourier lorsque approche de 0 (de telles distributions apparaissent comme caractères de représentations de groupes de Lie nilpotents). On étend des résultats de L. Corwin et F.P. Greenleaf (Comm. on Pure and Applied Math., 31 (1975), 681–705) au cas où le gradient de la partie de homogène de plus haut degré...
Majorizing measures and proportional subsets of bounded orthonormal systems..
Mapping properties of fundamental operators in harmonic analysis related to Bessel operators
We obtain sharp power-weighted , weak type and restricted weak type inequalities for the heat and Poisson integral maximal operators, Riesz transform and a Littlewood-Paley type square function, emerging naturally in the harmonic analysis related to Bessel operators.
Mapping properties of integral averaging operators
Characterizations are obtained for those pairs of weight functions u and v for which the operators with a and b certain non-negative functions are bounded from to , 0 < p,q < ∞, p≥ 1. Sufficient conditions are given for T to be bounded on the cones of monotone functions. The results are applied to give a weighted inequality comparing differences and derivatives as well as a weight characterization for the Steklov operator.
Mapping properties of maximal operators
Mapping properties of the elliptic maximal function.
We prove that the elliptic maximal function maps the Sobolev space W4,eta(R2) into L4(R2) for all eta > 1/6. The main ingredients of the proof are an analysis of the intersectiQn properties of elliptic annuli and a combinatorial method of Kolasa and Wolff.