The three-line theorem on the octonions is obtained, which generalizes the result of J. Peetre and P. Sj?lin from the associative Clifford algebra to non-associative octonion algebra.
Let D be the unit disk in the complex plane with the weighted measure $d\mu _\beta \left( z \right) = \frac{{\beta + 1}}{\pi }\left( {1 - \left| z \right|^2 } \right)^\beta dm\left( z \right)\left( {\beta > - 1} \right)$ . Then $L^2 \left( {D, d\mu _\beta \left( z \right)} \right) = \oplus _{k = 0}^\infty \left( {A_k^\beta \oplus \bar A_k^\beta } \right)$ is the orthogonal direct sum decomposition. In this paper, we define the Hankel and Toeplitz type operators, and study the boundedness, compactness and Sp-criteria for them.
The singular integral operatorTα,βf（x）=p.v.∫R^n[e^i｜y｜^-βΩ（y’）]/[｜y｜^n＋α]f（x-y）dy,defined for all test functions f is studied, where Ω（y＇） is a distribution on the unit sphere S^n-1 satisfying certain cancellation condition. It is proved that Tα,β is a bounded operator from the Triebel-Lizorkin space Fp^s,q to the Triebel-Lizorkin space Fp^s＋γ,q, provided that Ω（y＇） is a distribution in the Hardy space H^r（S^n-1） with r = （n - 1）/（n - 1 ＋ γ）.
Ye Xiaofeng Dept.of Math.,Zhejiang Univ.,Hangzhou 310027,China
