Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-28T03:28:29.532Z Has data issue: false hasContentIssue false

Representations with Weighted Frames and Framed Parabolic Bundles

Published online by Cambridge University Press:  20 November 2018

J. C. Hurtubise
Affiliation:
Department of Mathematics and Statistics, McGill University email: hurtubis@math.mcgill.ca
L. C. Jeffrey
Affiliation:
Department of Mathematics, University of Toronto email: jeffrey@math.utoronto.ca
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

There is a well-known correspondence (due to Mehta and Seshadri in the unitary case, and extended by Bhosle and Ramanathan to other groups), between the symplectic variety ${{M}_{h}}$ of representations of the fundamental group of a punctured Riemann surface into a compact connected Lie group $G$, with fixed conjugacy classes $h$ at the punctures, and a complex variety ${{\mathcal{M}}_{h}}$ of holomorphic bundles on the unpunctured surface with a parabolic structure at the puncture points. For $G\,=\,\text{SU}\left( 2 \right)$, we build a symplectic variety $P$ of pairs (representations of the fundamental group into $G$, “weighted frame” at the puncture points), and a corresponding complex variety $\mathcal{P}$ of moduli of “framed parabolic bundles”, which encompass respectively all of the spaces ${{M}_{h}}$, ${{\mathcal{M}}_{h}}$, in the sense that one can obtain ${{M}_{h}}$ from $P$ by symplectic reduction, and ${{\mathcal{M}}_{h}}$ from $\mathcal{P}$ by a complex quotient. This allows us to explain certain features of the toric geometry of the $\text{SU(2)}$ moduli spaces discussed by Jeffrey and Weitsman, by giving the actual toric variety associated with their integrable system.

Keywords

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2000

References

[AMM] Alekseev, A., Malkin, A. and Meinrenken, E., Lie group valued moment maps. J. Differential Geom. 48(1998), 445495.Google Scholar
[AMM2] Alekseev, A., Duistermaat-Heckman distributions for group valued moment maps. Preprint, math.DG/9903087, 31 pages.Google Scholar
[AB] Atiyah, M. F. and Bott, R., The Yang-Mills equations over Riemann surfaces. Philos. Trans. Roy. Soc. Lond. A308(1982), 523615.Google Scholar
[Bh] Bhosle, U., Parabolic vector bundles on curves. Ark. Mat. 27(1989), 1522.Google Scholar
[D] Delzant, T., Hamiltoniens périodiques et images convexes de l’application moment. Bull. Soc. Math. France 116(1988), 315339.Google Scholar
[Do] Donaldson, S. K., Gluing techniques in the cohomology of moduli spaces. In: Topological methods in modern mathematics (Stony Brook, NY, 1991), Publish or Perish, Houston, TX, 1993, 137170.Google Scholar
[Gi] Gieseker, D., On the moduli of vector bundles on algebraic surfaces. Ann.Math. 106(1977), 4560.Google Scholar
[G1] Goldman, W., Invariant functions on Lie groups and Hamiltonian flows of surface group representations. Invent. Math. 85(1986), 263302.Google Scholar
[G2] Goldman, W., The symplectic nature of fundamental groups of surfaces. Adv. Math. 54(1980), 200225.Google Scholar
[GJS] Guillemin, V., Jeffrey, L. and Sjamaar, R., Imploded cross-sections. Preprint.Google Scholar
[GS] Guillemin, V. and Sternberg, S., Symplectic Techniques in Physics. Cambridge University Press, 1984.Google Scholar
[H] Huebschmann, J., On the variation of the Poisson structures of certain moduli spaces. Preprint, dgga/ 9710033; Math. Ann., to appear.Google Scholar
[HL] Huybrechts, D. and Lehn, M., Stable pairs on curves and surfaces. J. Algebraic Geom. 4(1995), 67104.Google Scholar
[J1] Jeffrey, L. C., Extended moduli spaces of flat connections on Riemann surfaces. Math. Ann. 298(1994), 667692.Google Scholar
[J2] Jeffrey, L. C., Symplectic forms on moduli spaces of flat connections on 2-manifolds. In: Proceedings of the Georgia International Topology Conference (Athens, GA, 1993) (ed. W. Kazez), Amer. Math. Soc./International Press AMS/IP Stud. Adv. Math. 2(1997), 268281.Google Scholar
[JW] Jeffrey, L. C. and Weitsman, J., Bohr-Sommerfeld orbits in the moduli space of flat connections and the Verlinde dimension formula. Comm. Math. Phys. 150(1992), 593630.Google Scholar
[MFK] Mumford, D., Fogarty, J. and Kirwan, F., Geometric Invariant Theory. Springer-Verlag, 1994, chap. 8.2.Google Scholar
[MS] Mehta, V. and Seshadri, C. S., Moduli of vector bundles on curves with parabolic structure. Math. Ann. 248(1980), 205239.Google Scholar
[MW] Meinrenken, E. and Woodward, C., A symplectic proof of Verlinde factorization. J. Differential Geom., to appear.Google Scholar
[NS] Narasimhan, M. S. and Seshadri, C. S., Stable and unitary vector bundles on a compact Riemann surface. Ann. of Math. 82(1965), 540567.Google Scholar
[Th] Thaddeus, M., Geometric invariant theory and flips. J. Amer. Math. Soc. 9(1996), 691723.Google Scholar