In 2007, Fan, Jarvis, and Ruan constructed an analogue of the Gromov-Witten (GW) theory of hypersurfaces in weighted projective spaces. The new theory is attached to quasi-homogeneous polynomial singularities and is usually called Fan-Jarvis-Ruan-Witten theory (FJRW). It is part of the general picture of Witten, where GW and FJRW theories arise as two distinct GIT quotients of the same model. I will first explain this idea under the light of mirror symmetry. Then I will present FJRW theory and the geometric problem it illustrates. In particular, I will highlight a geometric property called concavity. For now, it is a necessary condition for explicit results on GW theory of hypersurfaces. But on the FJRW side, the situation has recently changed and I will describe my method based on Koszul cohomology to overcome this difficulty. As a consequence, I obtain a mirror symmetry theorem without concavity.[-]

Mirzakhani's recursion for Weil-Petersson volumes was shown by Eynard and Orantin to be equivalent to Topological Recursion with a specific choice of spectral curve. However, such a recursion is known to produce formal power series with factorially growing coefficient which, according to the theory of Resurgence, should be upgraded to “transseries” via the computation of non-perturbative contributions (i.e. instantons). In this talk I will show how a non-perturbative formulation of Topological Recursion allows for the computation of such contributions which, through simple resurgent relations, allow to obtain large genus asymptotics of Weil-Petersson volumes.[-]