Real Analytic Sets in Complex Spaces and CR maps

Abstract

If $R$ is a real analytic set in $\C^n$ (viewed as ${\mathbb{R}}^{2n}$), then for any point $p\in R$ there is a uniquely defined germ $X_p$ of the smallest complex analytic variety which contains $R_p$, the germ of $R$ at $p$. It is shown that if $R$ is irreducible of constant dimension, then the function $p\to \dim X_p$ is constant on a dense open subset of $R$. As an application it is proved that a continuous map from a real analytic CR manifold $M$ into $\C^N$ which is CR on some open subset of $M$ and whose graph is a real analytic set in $M\times \C^N$ is necessarily CR everywhere on $M$.