Sumihiro's theorem
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.
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
gollark: When I hear "when i hear "when i hear "complex player economy simulator" i think "vehicular shoe car mobile trainers"" i think "complex vehicular coral dot shoes online mobile car trainers"" I think "at least this recursion thing is bounded by Discord's message length limit".
gollark: You're on the [BEE EXPUNGED], ask the true heav there.
gollark: See, that seems like a reasonably reasonable reason.
gollark: That's a bad reason to do things.
gollark: Maybe you're just OFDM | GHZ2.
References
- Sumihiro, Hideyasu (1974), "Equivariant completion", J. Math. Kyoto Univ., 14: 1–28, doi:10.1215/kjm/1250523277.
External links
- Alper, Jarod; Hall, Jack; Rydh, David (2015). "A Luna étale slice theorem for algebraic stacks". arXiv:1504.06467 [math.AG].
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