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Characterizations of \(Q_p\) spaces in the unit ball of \(\mathbb C^n\). (English) Zbl 1179.32008

By writing \(B\), resp., \({\mathcal A}\) for the Euclidean unit ball of the complex \(n\)-space \(\mathbb C^n\) and the family of its holomorphic automorphisms, a holomorphic function \(f:B\to \mathbb C\) belongs to \(Q_p\) if \(\sup_{\varphi\in{\mathcal A}} \int_B |\nabla f(z)|^2 (1-| z|^2)^2 (1-|\varphi(z)|^2)^{np} \;d\lambda(z) <\infty\) where \(d\lambda(z):= (1-| z|^2)^{-n-1}\) in terms of the normalized Lebesgue measure \(d\nu\) on \(B\). Similarly, by definition, \(f\in Q_{p,0}\) if \(\lim_{| \varphi(0)| \to 1, \varphi\in{\mathcal A}} \int_B |\nabla f(z)|^2 (1-| z|^2)^2 (1-|\varphi(z)|^2)^{np} \;d\lambda(z) =0\).
The paper is aimed to give various derivative free and oscillation type characterizations of these relationships. A typical result, for instance Theorem 3, asserts that, in case of \(1-n^{-1} < p\leq 1\), we have \(f\in Q_p\) if and only if \(\sup_{\varphi\in{\mathcal A}} \int_B [\text{MO}(f)(z)]^2 (1-| \varphi(z)|^2)^{np} \;d\lambda(z) < \infty\) where \(\text{MO}(f)(z):= \big[ \int_B | f(w)-f(z)|^2 (1-| z|^2 )^{n+1} | 1 - \langle z,w\rangle^{-2(n+1)} \;d\nu(w) \big]^{1/2}\). To give more insight, the following part of Theorem 5 is also worth to be mentioned: given \(r>0\) and \(1-n^{-1}< p\leq 1\), we have \(f\in Q_p\) if and only if \(\sup_{\varphi\in{\mathcal A}} \int_B \big( \sup_{w\in E(z,r)} | f(z)-f(w)| (1-| \varphi(z)|^2)^{np/4} (1-| \varphi(w)|^2)^{np/4} \big)^2 \;d\lambda(z) < \infty\) where \( E(z,r):= \{ w\in B:\;|\varphi(w)| < r \;\text{for some} \;\varphi\in{\mathcal A} \;\text{with} \;\varphi(0)=z\}\). The corresponding descriptions for \(f\in Q_{p,0}\) are obtained in both cases by replacing the terms \(\sup_{\varphi\in{\mathcal A}}\) and \(<\infty\) with \(\lim_{| \varphi(0)|\to 1 , \varphi\in{\mathcal A}}\) and \(=0\), respectively.

MSC:

32M17 Automorphism groups of \(\mathbb{C}^n\) and affine manifolds
31C25 Dirichlet forms
Full Text: DOI

References:

[1] Hu, P.; Shi, J., Multipliers on Dirichlet-type spaces, Acta Math. Sin. (Engl. Ser.), 17, 263-272 (2001) · Zbl 1006.32006
[2] Hu, P.; Zhang, W., A new characterization of Dirichlet type spaces on the unit ball of \(C^n\), J. Math. Anal. Appl., 259, 453-461 (2001) · Zbl 1011.46021
[3] Li, B.; Ouyang, C., Higher radial derivative of functions of \(Q_p\) spaces and its applications, J. Math. Anal. Appl., 327, 2, 1257-1272 (2007) · Zbl 1111.32002
[4] Li, B.; Ouyang, C., Randomization of \(Q_p\) spaces on the unit ball of \(C^n\), Sci. China Ser. A, 48, Suppl., 306-317 (2005) · Zbl 1128.32004
[5] Li, S., Some new characterizations of Dirichlet type spaces on the unit ball of \(C^n\), J. Math. Anal. Appl., 324, 1073-1083 (2006) · Zbl 1108.32005
[6] Li, S.; Wulan, H., Characterizations of \(α\)-Bloch spaces on the unit ball, J. Math. Anal. Appl., 343, 1, 58-63 (2008) · Zbl 1204.32006
[7] Ouyang, C.; Yang, W.; Zhao, R., Möbius invariant \(Q_p\) spaces associated with the Green function on the unit ball, Pacific J. Math., 182, 69-99 (1998) · Zbl 0893.32005
[8] Pavlović, M.; Zhu, K., New characterizations of Bergman spaces, Ann. Acad. Sci. Fenn. Math., 33, 87-99 (2008) · Zbl 1147.32008
[9] Pavlović, M.; Zhu, K., Addendum to “New characterizations of Bergman spaces”, Ann. Acad. Sci. Fenn. Math., 34, 315-317 (2009) · Zbl 1168.32303
[10] Rudin, W., Function Theory in the Unit Ball of \(C^n (1980)\), Springer-Verlag: Springer-Verlag New York · Zbl 0495.32001
[11] Wulan, H.; Zhu, K., Derivative-free characterizations of \(Q_K\) spaces, J. Aust. Math. Soc., 82, 2, 283-295 (2007) · Zbl 1122.30033
[12] Xiao, J., Holomorphic \(Q\) Classes, Lecture Notes in Math., vol. 1767 (2001) · Zbl 0983.30001
[13] Xiao, J., Geometric \(Q_p\) Functions, Front. Math. (2006), Birkhäuser-Verlag · Zbl 1104.30036
[14] Yang, W., Carleson type measure characterizations of \(Q_p\) spaces, Analysis, 18, 345-349 (1998) · Zbl 0934.32006
[15] Yang, W., Vanishing Carleson type measure characterizations of \(Q_{p, 0}\), C. R. Math. Acad. Sci. Soc. R. Can., 21, 1-5 (1999) · Zbl 0933.32006
[16] Zhu, K., Spaces of Holomorphic Functions in the Unit Ball (2005), Springer-Verlag: Springer-Verlag New York · Zbl 1067.32005
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