Kirwan map

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In differential geometry, the Kirwan map, introduced by British mathematician Frances Kirwan, is the homomorphism

where

It is defined as the map of equivariant cohomology induced by the inclusion followed by the canonical isomorphism .

A theorem of Kirwan [1] says that if is compact, then the map is surjective in rational coefficients. The analogous result holds between the K-theory of the symplectic quotient and the equivariant topological K-theory of . [2]

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References

  1. Kirwan, F.C. (1984). Cohomology of Quotients in Complex and Algebraic Geometry. Mathematical Notes. Vol. 31. Princeton University Press. ISBN   978-0-691-21456-6.
  2. Harada, M.; Landweber, G. (2007). "Surjectivity for Hamiltonian G-spaces in K-theory". Trans. Amer. Math. Soc. 359 (12): 6001–25. arXiv: math/0503609 . doi:10.1090/S0002-9947-07-04164-5. JSTOR   20161853. S2CID   17690407.