Blowing down

In mathematics, blowing down is a type of geometric modification in algebraic geometry. It is the inverse operation of blowing up.

Related Topics:
Mathematics - Algebraic geometry - Blowing up

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On an algebraic surface, blowing down a curve lying on the surface is a typical effect of a birational transformation. The curves that blow down, to a non-singular point, are of a special kind: they are rational curves, with self-intersection number −1.

Related Topics:
Algebraic surface - Birational transformation - Non-singular point - Rational curve - Self-intersection number

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