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Sean Lawton and Daniel Ramras
Covering spaces of character varieties view print
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Published: |
June 16, 2015
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Keywords: |
character variety, moduli space, covering, path components, fundamental group, universal cover, properly discontinuous action |
Subject: |
57M10, 14D20, 32G13, 14L30 |
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Abstract
Let Γ be a finitely generated discrete group.
Given a covering map H→ G of Lie groups with G either compact or complex reductive, there is an induced covering map
Hom(Γ, H)→ Hom(Γ, G). We show that when
π1(G) is torsion-free
and Γ is free, free Abelian, or the fundamental group of a closed Riemann surface Mg,
this map induces a covering map between the corresponding moduli spaces of representations.
We give conditions under which this map is actually the universal covering,
leading to new information regarding fundamental groups of these moduli spaces. As an application,
we show that for g≧1, the stable moduli space
Hom(π1Mg, SU)/SU is homotopy equivalent
to
CP∞.
In the Appendix, Ho and Liu show
π0Hom(π1Mg, G) and
π1[G,G] are in bijective correspondence for all complex connected reductive Lie groups G.
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Acknowledgements
The first author was partially supported by the Simons Foundation (#245642) and the NSF-DMS (#1309376). The second author was partially supported by the Simons Foundation (#279007).
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Author information
Sean Lawton:
Department of Mathematical Sciences, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, USA
slawton3@gmu.edu
Daniel Ramras:
Department of Mathematical Sciences, Indiana University-Purdue University Indianapolis, 402 N. Blackford, LD 270, Indianapolis, IN 46202, USA
dramras@math.iupui.edu
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