Andreotti–Frankel theorem
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In mathematics, the Andreotti–Frankel theorem states that if V is a smooth affine variety of complex dimension n or, more generally, if V is any Stein manifold of dimension n, then in fact V is homotopy equivalent to a CW complex of real dimension at most n. In other words V has only half as much topology.
Consequently, if is a closed connected complex submanifold of complex dimension n. Then V has the homotopy type of a CW complex of real dimension . Therefore
- , for i > n
and
- , for i > n.
This theorem applies in particular to any smooth affine variety of dimension n.