Reyer Sjamaar

Professor of Mathematics and Director of Graduate Studies

551 Malott Hall

(607) 255-3624

Ph.D. (1990) Universiteit Utrecht, the Netherlands

Research Area

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 recent work concerns moment polytopes and leads to improved versions of certain eigenvalue inequalities in matrix analysis.

Selected Publications

Holomorphic slices, symplectic reduction and multiplicities of representations, Ann. Math. (2) 141 (1995), 87–129.

Singular reduction and quantization (with E. Meinrenken), Topology 38 (1998), 699–762.

Moment maps and Riemannian symmetric pairs (with L. O'Shea), Math. Ann.317 no. 3 (2000), 415–457.

Projections of coadjoint orbits, moment polytopes and the Hilbert-Mumford criterion (with A. Berenstein), J. Amer. Math. Soc. 13 no. 2 (2000), 433–466.

Convexity properties of Hamiltonian group actions (with V. Guillemin), CRM Monograph Series 26, American Mathematical Society, Providence, RI, 2005.

Group-valued implosion and parabolic structures (with J. Hurtubise and L. Jeffrey), Amer. J. Math. 128 no. 1 (2006), 167–214.