A Fatou-type Theorem for Harmonic Functions on Symmetric Spaces1 by S. Helgason and A. Koranyi
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چکیده
1. Introduction. The result to be proved in this article is that if u is a bounded harmonic function on a symmetric space X and x 0 any point in X then u has a limit along almost every geodesic in X starting at x 0 (Theorem 2.3). In the case when X is the unit disk with the non-Euclidean metric this result reduces to the classical Fatou theorem (for radial limits). When specialized to this case our proof is quite different from the usual one; in fact it corresponds to transforming the Poisson integral of the unit disk to that of the upper half-plane and using only a homogeneity property of the Poisson kernel. The kernel itself never enters into the proof.
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تاریخ انتشار 2005