English

Multiplicity-free Hamiltonian actions need not be K\"ahler

dg-ga 2008-02-03 v1 Differential Geometry

Abstract

We show that Tolman's example (of a six dimensional Hamiltonian T2T^2-space with isolated fixed points and no compatible K\"{a}hler structure) can be constructed from the flag variety U(3)/U(1)3U(3)/U(1)^3 by U(2)U(2)-equivariant symplectic surgery. This implies that Tolman's space has a ``transversal multiplicity-free'' action of U(2)U(2) and that Delzant's theorem ``every compact multiplicity-free torus action is K\"{a}hler'' \cite{D1} does not generalize to non-abelian actions.

Keywords

Cite

@article{arxiv.dg-ga/9506009,
  title  = {Multiplicity-free Hamiltonian actions need not be K\"ahler},
  author = {Chris Woodward},
  journal= {arXiv preprint arXiv:dg-ga/9506009},
  year   = {2008}
}

Comments

LaTeX using epic, eepic. 10 pages, 4 figures