Reyer Sjamaar


Research Focus

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.


  • 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. 

MATH Courses - Spring 2024

MATH Courses - Fall 2024