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Stratification of \(\mathrm{SU}(r)\)-character varieties of twisted Hopf links. (English) Zbl 07915461

Gothen, Peter (ed.) et al., Moduli spaces and vector bundles – new trends. VBAC 2022 conference in honor of Peter Newstead’s 80th birthday, University of Warwick, Coventry, United kingdom, July 25–29, 2022. Providence, RI: American Mathematical Society (AMS). Contemp. Math. 803, 257-278 (2024).
Summary: We describe the geometry of the character variety of representations of the fundamental group of the complement of a Hopf link with \(n\) twists, namely \(\Gamma_n=\langle x,y\mid[x^n,y]=1 \rangle\) into the group \(\mathrm{SU}(r)\). For arbitrary rank, we provide geometric descriptions of the loci of irreducible and totally reducible representations. In the case \(r=2\), we provide a complete geometric description of the character variety, proving that this \(\mathrm{SU}(2)\)-character variety is a deformation retract of the larger \(\mathrm{SL}(2,\mathbb{C})\)-character variety, as conjectured by Florentino and Lawton. In the case \(r=3\), we also describe different strata of the \(\mathrm{SU}(3)\)-character variety according to the semi-simple type of the representation.
For the entire collection see [Zbl 07913515].

MSC:

14M35 Character varieties
57K31 Invariants of 3-manifolds (including skein modules, character varieties)
53Cxx Global differential geometry

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