21 citations · 86 across the 9 of their papers we have counts for
9 papers
The Hitchin connection in arbitrary characteristic
Thomas Baier, Michele Bolognesi, Johan Martens +1
We give an algebro-geometric construction of the Hitchin connection, valid also in positive characteristic (with a few exceptions). A key ingredient is a substitute for the Narasim…
Group Compactifications and Moduli Spaces
Johan Martens
We give a summary of joint work with Michael Thaddeus that realizes toroidal compactifcations of split reductive groups as moduli spaces of framed bundles on chains of rational cur…
Contraction of Hamiltonian -spaces
Joachim Hilgert, Christopher Manon, Johan Martens
In the spirit of recent work of Harada-Kaveh and Nishinou-Nohara-Ueda, we study the symplectic geometry of Popov's horospherical degenerations of complex algebraic varieties with t…
The Witten-Reshetikhin-Turaev invariant for links in finite order mapping tori I
Jørgen Ellegaard Andersen, Benjamin Himpel, Søren Fuglede Jørgensen +2
We state Asymptotic Expansion and Growth Rate conjectures for the Witten-Reshetikhin-Turaev invariants of arbitrary framed links in 3-manifolds, and we prove these conjectures for…
Variations on a theme of Grothendieck
Johan Martens, Michael Thaddeus
Grothendieck and Harder proved that every principal bundle over the projective line with split reductive structure group (and trivial over the generic point) can be reduced to a ma…
On Non-Abelian Symplectic Cutting
Johan Martens, Michael Thaddeus
We discuss symplectic cutting for Hamiltonian actions of non-Abelian compact groups. By using a degeneration based on the Vinberg monoid we give, in good cases, a global quotient d…
Compactifications of reductive groups as moduli stacks of bundles
Johan Martens, Michael Thaddeus
Let G be a split reductive group. We introduce the moduli problem of "bundle chains" parametrizing framed principal G-bundles on chains of lines. Any fan supported in a Weyl chambe…
Moduli of Parabolic Higgs Bundles and Atiyah Algebroids
Marina Logares, Johan Martens
In this paper we study the geometry of the moduli space of (non-strongly) parabolic Higgs bundles over a Riemann surface with marked points. We show that this space possesses a Poi…
Equivariant volumes of non-compact quotients and instanton counting
Johan Martens
Motivated by Nekrasov's instanton counting, we discuss a method for calculating equivariant volumes of non-compact quotients in symplectic and hyper-Kähler geometry by means of the…