We study the boundedness in $L^p(𝕊^n)$ of the projections onto spaces of functions with spectrum contained in horizontal strips. We obtain some results concerning convergence along nonisotropic regions of harmonic extensions of functions in $L^p(𝕊^n)$ with spectrum included in these horizontal strips.
Departament de Matemàtica Aplicada i Anàlisi, Facultat de Matemàtiques, Universitat de Barcelona, Gran Via 585, 08071 Barcelona, Spain
Bibliografia
[AhBr] P. Ahern and J. Bruna, Maximal and area integral characterizations of Hardy-Sobolev spaces in the unit ball of $ℂ^n$, Rev. Mat. Iberoamericana 4 (1988), 123-153.
[AhCa] P. Ahern and C. Cascante, Exceptional sets for Poisson integrals of potentials on the unit sphere in $ℂ^n$, p≤1$, Pacific J. Math. 153 (1992), 1-13.
[Al] A. B. Aleksandrov, Several Complex Variables II, Encyclopaedia Math. Sci. 8, G. M. Khenkin and A. G. Vitushkin (eds.), Springer, 1991.
[BeLo] J. Bergh and J. Löfström, Interpolation Spaces. An Introduction, Springer, 1976.
[BoCl] A. Bonami et J.-L. Clerc, Sommes de Cesàro et multiplicateurs des développements en harmoniques sphériques, Trans. Amer. Math. Soc. 183 (1973), 223-263.
[BrCa] J. Bruna and C. Cascante, Restriction to transverse curves of some spaces of functions in the unit ball, Michigan Math. J. 36 (1989), 387-401.
[BrOr] J. Bruna and J. M. Ortega, Closed finitely generated ideals in algebras of holomorphic functions and smooth to the boundary in strictly pseudoconvex domains, Math. Ann. 268 (1984), 137-157.
[CaOr] C. Cascante and J. M. Ortega, A characterisation of tangential exceptional sets for $H_α^p$, α p=n, Proc. Roy. Soc. Edinburgh 126 (1996), 625-641.
[Ch] E. M. Chirka, The Lindelöf and Fatou theorems in $ℂ^n$, Mat. Sb. 92 (1973), 622-644 (in Russian).
[Do] E. Doubtsov, thesis, Université Bordeaux I, 1995.
[GaRu] J. García-Cuerva and J. L. Rubio de Francia, Weighted Norm Inequalities and Related Topics, North-Holland, 1985.
[Ge] D. Geller, Some results in $H^p$ theory for the Heisenberg group, Duke Math. J. 47 (1980), 365-390.
[Kr1] V. G. Krotov, Estimates for maximal operators connected with boundary behavior and their applications, Trudy Mat. Inst. Steklov. 190 (1989), 117-138 (in Russian); English transl.: Proc. Steklov Inst. Math. 1 (1992), 123-144.
[Kr2] V. G. Krotov, A sharp estimate of the boundary behavior of functions in the Hardy-Sobolev classes $H_α^p(𝔹^n)$ in the critical case α p=n, Dokl. Akad. Nauk SSSR 319 (1991), 42-45 (in Russian); English transl.: Soviet Math. Dokl. 44 (1992), 36-39.
[Li] E. Lindelöf, Sur un principe générale de l'analyse et ses applications à la théorie de la représentation conforme, Acta Soc. Sci. Fenn. 46 (1915), 1-35.
[NaRoStWa] A. Nagel, J. P. Rosay, E. M. Stein and S. Wainger, Estimates for the Bergman and Szegő kernels in $ℂ^2$, Ann. of Math. 129 (1989), 113-149.
[NaRu] A. Nagel and W. Rudin, Local boundary behavior of bounded holomorphic functions, Canad. J. Math. 30 (1978), 583-592.
[NaRuSh] A. Nagel, W. Rudin and J. H. Shapiro, Tangential boundary behavior of functions in Dirichlet-type spaces, Ann. of Math. 116 (1982), 331-360.
[NaWa] A. Nagel and S. Wainger, Limits of bounded holomorphic functions along curves, in: Recent Developments in Several Complex Variables, J. E. Fornaess (ed.), Princeton Univ. Press, 1981, 327-344.
[Ru] W. Rudin, Function Theory in the Unit Ball of $ℂ^n$, Springer, 1980.
[St] J. D. Stafney, The spectrum of an operator on an interpolation space, Trans. Amer. Math. Soc. 144 (1969), 333-349.
[Su] J. Sueiro, Tangential boundary limits and exceptional sets for holomorphic functions in Dirichlet-type spaces, Math. Ann. 286 (1990), 661-678.
[TrEr] F. G. Tricomi and A. Erdélyi, The asymptotic expansion of a ratio of gamma functions, Pacific J. Math. 1 (1951), 133-142.
[Zy] A. Zygmund, On a theorem of Littlewood, Summa Brasil. Math. 2 (1949), 1-7.