Group-valued Implosion and Parabolic Structures

dc.creatorHurtubise, Jacques
dc.creatorJeffrey, Lisa
dc.creatorSjamaar, Reyer
dc.date2004-02-27
dc.date.accessioned2026-07-07T06:30:20Z
dc.date.available2026-07-07T06:30:20Z
dc.descriptionThe purpose of this paper is twofold. First we extend the notion of symplectic implosion to the category of quasi-Hamiltonian $K$-manifolds, where $K$ is a simply connected compact Lie group. The imploded cross-section of the double $K\times K$ turns out to be universal in a suitable sense. It is a singular space, but some of its strata have a nonsingular closure. This observation leads to interesting new examples of quasi-Hamiltonian $K$-manifolds, such as the ``spinning $2n$-sphere'' for $K=\SU(n)$. Secondly we construct a universal (``master'') moduli space of parabolic bundles with structure group $K$ over a marked Riemann surface. The master moduli space carries a natural action of a maximal torus of $K$ and a torus-invariant stratification into manifolds, each of which has a symplectic structure. An essential ingredient in the construction is the universal implosion. Paradoxically, although the universal implosion has no complex structure (it is the four-sphere for $K=\SU(2)$), the master moduli space turns out to be a complex algebraic variety.
dc.description39 pages
dc.identifierhttps://arxiv.org/abs/math/0402464
dc.identifierhttp://arxiv.org/abs/math/0402464
dc.identifierAmer. J. Math. 128 (2006), no. 1, 167--214
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/98316
dc.subjectSymplectic Geometry
dc.subject53D20; 53D30
dc.titleGroup-valued Implosion and Parabolic Structures
dc.typetext

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