Abstract: Non-abelian Hodge theory relates representations of the fundamental group of a compact Riemann surface X into a Lie group G with holomorphic objects on X known as Higgs bundles, introduced by Hitchin more than 35 years ago. Starting with the case in which G is the circle, and the 19th century Abel-Jacobi's theory, we will move to the case of G=SL(2,R) and the relation to Teichmüller t...
AbstractA classical theorem due to Birkhoff states that on a real or a complex symplectic manifold a function near its Morse critical point can be transformed by formal symplectomorphism into a power series in the pairwise sums of squares of the local coordinates, called its "Birkhoff normal form". A result of Sjöstrand says that, given certain conditions, one can compute the eigenvalues of the...