Bargmann-Fock extension from Singular Hypersurfaces

Abstract

We establish sufficient conditions for extension of weighted square integrable holomorphic functions from a possibly singular hypersurface to the ambient affine space. The norms we use are the so-called Bargmann-Fock norms, and thus there are restrictions on the singularities and the density of the hypersurface. Our sufficient conditions are that it has density less than 1, and is uniformly flat in a sense that extends to singular varieties the notion of uniform flatness introduced earlier. We present an example of Ohsawa showing that uniform flatness is not necessary for extension in the singular case, and find an example showing that, for rather different reasons, it is also not necessary for the smooth case. The latter answers in the negative a question posed in an earlier paper of the second author.