Vanessa Hahn (UP)
Pavel Hajek (Universität Augsburg)
For a closed oriented Riemannian manifold M, we consider integrals associated to trivalent ribbon graphs decorated with harmonic forms at exterior vertices and the Green kernel G(x,y) at interior edges. We use these integrals to construct a chain model for the Chas-Sullivan string topology of M. In my talk, I will discuss some analytical issues related to the singularity of G(x,y) at x=y and its resolution using a blow-up construction. The theory is based on ongoing work of K. Cieliebak and E. Volkov.