Alphabeta Math

Moment Maps and Symplectic Reduction — Examples

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1 · Prerequisites
Abstract Algebra
Category Theory
Combinatorics
Commutative Algebra
Coxeter Groups
Differential Geometry
Functional Analysis
Homological Algebra
Lie Theory
Linear Algebra
Real Analysis
Set Theory
Topology
2 · Logical flowchart

3 · Items

Example

Circle rotation on complex n-space and its quadratic moment map

Example

Complex projective space as a circle symplectic reduction

Example

Weighted circle actions and weighted projective singular quotients

Example

Angular momentum as the moment map for rotations of a cotangent bundle

Example

Cotangent reduction for a principal bundle at zero

Example

The two-sphere as a coadjoint orbit of SO(3)

Example

Grassmannians from unitary symplectic reduction

Example

Diagonal action and addition of angular momenta

Example

The shifting trick for a nonzero coadjoint orbit

Example

The reduced harmonic oscillator flow on projective space

Counterexample

An irrational flow on a symplectic torus is symplectic but not Hamiltonian

Counterexample

The zero angular-momentum level has nonfree points and no regular reduction

Sources