Problems / geometry-topology
geometry-topology / Kahler geometry; several complex variables
Yau's question on bounded holomorphic functions: does a complete simply connected Kahler manifold with sectional curvature at most −a2<0 carry a nonconstant bounded holomorphic function?
Theorem 1.1: for some finite m≥2 there is a domain T⊂Cm, diffeomorphic to R2m, with a complete Kahler metric g satisfying Secg≤−1 and H∞(T)=C: every bounded holomorphic function is constant, so the Caratheodory pseudometric vanishes. This disproves the universal assertion in the one-sided question, and also answers Wu's 1967 bounded-domain question negatively under its hypotheses. The sectional curvatures are unbounded below, so the question under a two-sided bound −b2≤Sec≤−a2 remains open; the dimension is large and not made explicit.