Abstract
It is well known that the reproducing kernel of the space of spherical harmonics of fixed homogeneity is given by a Gegenbauer polynomial. By going over to complex variables and restricting to suitable bihomogeneous subspaces, one obtains a reproducing kernel expressed as a Jacobi polynomial, which leads to Koornwinder’s celebrated result on the addition formula. In the present paper, the space of Hermitian monogenics, which is the space of polynomial bihomogeneous null-solutions of a set of two complex conjugated Dirac operators, is considered. The reproducing kernel for this space is obtained and expressed in terms of sums of Jacobi polynomials. This is achieved through use of the underlying Lie superalgebra \(\mathfrak {sl}(1|2)\), combined with the equivalence between the \(L^2\) inner product on the unit sphere and the Fischer inner product. The latter also leads to a new proof in the standard Dirac case related to the Lie superalgebra \(\mathfrak {osp}(1|2)\).
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References
Andrews, G., Askey, R., Roy, R.: Special Functions. Cambridge University Press, Cambridge (1999)
Askey, R.: Orthogonal Polynomials and Special Functions. SIAM, Philadelphia (1975)
Bezubik, A., Strasburger, A.: On spherical expansions of smooth \(SU(n)\)-zonal functions on the unit sphere in \(\mathbb{C}^n\). J. Math. Anal. Appl. 404, 570–578 (2013)
Brackx, F., Bureš, J., De Schepper, H., Eelbode, D., Sommen, F., Souček, V.: Fundaments of Hermitean Clifford analysis. Part I: complex structure. Complex Anal. Oper. Theory 1, 341–365 (2007)
Brackx, F., Bureš, J., De Schepper, H., Eelbode, D., Sommen, F., Souček, V.: Fundaments of Hermitean Clifford analysis part II: splitting of h-monogenic equations. Complex Var. Elliptic Equ. 52, 1063–1079 (2007)
Brackx, F., Delanghe, R., Sommen, F.: Clifford Analysis. Pitman (Advanced Publishing Program), Boston (1982)
Brackx, F., De Schepper, H., Eelbode, D., Souček, V.: The Howe dual pair in Hermitean Clifford analysis. Rev. Mat. Iberoam. 26(2), 449–479 (2010)
Brackx, F., De Schepper, H., Souček, V.: Fischer decompositions in Euclidean and Hermitean Clifford analysis. Arch. Math. (Brno) 46, 301–321 (2010)
Dai, F., Xu, Y.: Approximation Theory and Harmonic Analysis on Spheres and Balls. Springer, London (2013)
De Bie, H., Ørsted, B., Somberg, P., Souček, V.: The Clifford deformation of the Hermite semigroup. SIGMA 9, 010 (2013). doi:10.3842/SIGMA.2013.010
Delanghe, R., Sommen, F., Souček, V.: Clifford Algebra and Spinor-Valued Functions. Kluwer, Dordrecht (1992)
Eelbode, D.: Irreducible \(\mathfrak{sl}(m)\)-modules of Hermitean monogenics. Complex Var. Elliptic Equ. 53(10), 975–987 (2008)
Eelbode, D.: Stirling numbers and spin-Euler polynomials. Exp. Math. 16, 55–66 (2007)
Fischer, E.: Über die Differentiationsprozesse der Algebra. J. für Math. 148, 1–78 (1917)
Koornwinder, T.H.: The addition formula for Jacobi polynomials and spherical harmonics. SIAM J. Appl. Math. 25, 236–246 (1973)
Shapiro, H.: An algebraic theorem of E. Fischer, and the holomorphic Goursat problem. Bull. Lond. Math. Soc. 21(6), 513–537 (1989)
Stein, E., Weiss, G.: Introduction to Fourier Analysis on Euclidean Spaces. Princeton University Press, Princeton (1971)
Szegő, G.: Orthogonal Polynomials. American Mathematical Society, New York (1939)
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Communicated by Tom H. Koornwinder.
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De Bie, H., Sommen, F. & Wutzig, M. Reproducing Kernels for Polynomial Null-Solutions of Dirac Operators. Constr Approx 44, 339–383 (2016). https://doi.org/10.1007/s00365-016-9326-6
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DOI: https://doi.org/10.1007/s00365-016-9326-6
Keywords
- Reproducing kernels
- Gegenbauer polynomials
- Jacobi polynomials
- Spherical harmonics
- Dirac operator
- Clifford analysis