Bourbaki

Lemma 3

Tag 00XP, permanent. Cite it as [Bourbaki, Tag 00XP].

Lie Groups and Lie Algebras, chapter VII, Appendix 2. A connectedness property

Let X be a finite dimensional connected complex-analytic manifold and let A be a subset of X satisfying the following condition:

For any x∈Xx\in X, there exists an analytic function germ fxf_x, not vanishing

at xx, such that the germ of A at xx is contained in the germ at xx of the set

of zeros of fxf_x.

Then X -- A is dense in X and connected.

The density of X-- A follows from Differentiable and Analytic Manifolds, Results, 3.2.5. We can assume that A is closed (General Topology, Chap. I, §11, no. 1, Prop. 1). For any x∈Xx\in X, there exists an open neighbourhood V of xx and an isomorphism cc from V to an open ball in Cn\mathbf{C}^n such that c(A∩V)c(A\cap V) is contained in the set of zeros of a holomorphic function not identically zero on c(V)c(V). Then, by Lemma 2,V∩(X2, V\cap (X -- A) is connected. In view of Lemma 1, this proves that X -- A is connected.

Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.

Cited by

Nothing.

Cites

  • Lemma 1
  • General Topology, Chap. I, §11, no. 1, Prop. 1 not in this corpus
Transcribed from the printed volume. Not translated.