Sumihiro's theorem

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In algebraic geometry, Sumihiro's theorem, introduced by ( Sumihiro 1974 ), states that a normal algebraic variety with an action of a torus can be covered by torus-invariant affine open subsets.

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The "normality" in the hypothesis cannot be relaxed. [1] The hypothesis that the group acting on the variety is a torus can also not be relaxed. [2]

Notes

  1. Cox, David A.; Little, John B.; Schenck, Henry K. (2011). Toric Varieties. American Mathematical Soc. ISBN   978-0-8218-4819-7.
  2. "Bialynicki-Birula decomposition of a non-singular quasi-projective scheme". MathOverflow. Retrieved 2023-03-10.

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