We study the complex geometry of generalized Kepler manifolds, defined in Jordan theoretic terms, introduce Hilbert spaces of holomorphic functions defined by radial measures, and find the complete asymptotic expansion of the corresponding reproducing kernels for Kähler potentials, both in the flat and bounded setting.
IntroductionFor a Kähler manifold, with (integral) Kähler form ω and quantizing line bundle L, it is a fundamental problem to measure the deviation of the 'classical' curvature νω of the ν-th power L ν from the 'quantum' curvature ω ν obtained by the pull-back of the Fubini-Study form on the projective space of holomorphic sections. This relationship is usually expressed in terms of an asymptotic expansion of ω ν in inverse powers of the deformation parameter ν, known as the TYZ-expansion of the Kempf distortion function. Closely related is the asymptotic expansion of the reproducing kernel function of the Hilbert space of holomorphic sections, a fundamental tool in complex analysis. In this paper we carry out this program for an important class of algebraic varieties, the so-called Kepler varieties defined in a Jordan theoretic setting, which generalize the well-known determinantal varieties in matrix spaces. These varieties and their regular part (Kepler manifolds) are of interest from several points of view. As algebraic varieties, we show that Kepler varieties are normal, and classify invariant holomorphic differential forms of top-degree. Using a natural polar decomposition, these manifolds carry radial measures giving rise to reproducing kernel Hilbert spaces of holomorphic functions. The most interesting radial measures on Kepler manifolds come from Kähler potentials, both in the flat and bounded setting. For these, the reproducing kernel functions are related to multi-variable hypergeometric functions of type 1 F 1 and 2 F 1 . Among our main results is the asymptotic expansion of these hypergeometric functions, which in the multi-variable case is quite challenging, and leads to the TYZ-expansion mentioned above.Using chains of Peirce spaces in Jordan triples, the approach presented here can be extended to yield asymptotic expansions of TYZ-type in a quite general setting of homogeneous flag varieties.
Generalized Kepler manifoldsIt is well-known that hermitian bounded symmetric domains are characterized (via their holomorphic tangent space at the origin) by the so-called hermitian Jordan triples. Geometrically, the Jordan triple product gives the holomorphic part of the Riemann curvature tensor. We use [14] as our standard reference concerning Jordan algebras and analysis on symmetric cones. For the more general Jordan triples, see [20]. Let Z be an irreducible hermitian Jordan triple of rank r. Let {u; v; w} =: D(u, v)w denote the Jordan triple product of u, v, w ∈ Z. Consider the Bergman operators B(u, v) ≡ B u,v := id − D(u, v) + Q u Q v 1991 Mathematics Subject Classification. Primary 32M15; Secondary 14M12, 17C36, 46E22, 47B35.