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Reyer Sjamaar


Reyer Sjamaar

Educational Background

  • June 1990: Ph. D., Universiteit Utrecht (UU), the Netherlands.



  • Mathematics

Graduate Fields

  • Mathematics


Symplectic geometry

I study actions of Lie groups on symplectic manifolds. This is an area of differential geometry related to algebraic geometry and mathematical physics.  Some of my work concerns moment polytopes and leads to improved versions of certain eigenvalue inequalities in matrix analysis.


Spring 2022

Fall 2022


  • Character formulæ and GKRS multiplets in equivariant K-theory (with G. Landweber), Selecta Math. (N.S.) 19 (2013), no. 1, 49–95.
  • Divided differences and the Weyl character formula in equivariant K-theory (with M. Harada and G. Landweber), Math. Res. Lett. 17 (2010), no. 3, 507–527.
  • Torsion and abelianization in equivariant cohomology (with T. Holm), Transform. Groups 13 (2008), no. 3–4, 585–615.
  • Group-valued implosion and parabolic structures (with J. Hurtubise and L. Jeffrey), Amer. J. Math. 128 no. 1 (2006), 167–214.
  • Convexity properties of Hamiltonian group actions (with V. Guillemin), CRM Monograph Series 26, American Mathematical Society, Providence, RI, 2005.